Disubstituted alkyl-8-azabicyclo[3.2.1]octane compounds as mu opioid receptor antagonists

ABSTRACT

The invention provides novel 8-azabicyclo[3.2.1]octane compounds of formula (I): 
                         
where the variables are defined in the specification, or a pharmaceutically-acceptable salt thereof, that are antagonists at the mu opioid receptor. The invention also provides pharmaceutical compositions comprising such compounds, methods of using such compounds to treat conditions associated with mu opioid receptor activity, and processes and intermediates useful for preparing such compounds.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/966,281, filed on Aug. 27, 2007, the disclosure of which is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention is directed to 8-azabicyclo[3.2.1]octane compounds which are useful as mu opioid receptor antagonists. The invention is also directed to pharmaceutical compositions comprising such compounds, methods of using such compounds for treating or ameliorating medical conditions mediated by mu opioid receptor activity, and processes and intermediates useful for preparing such compounds.

2. State of the Art

It is now generally understood that endogenous opioids play a complex role in gastrointestinal physiology. Opioid receptors are expressed throughout the body, both in the central nervous system and in peripheral regions including the gastrointestinal (GI) tract.

Compounds which function as agonists at opioid receptors, of which morphine is a prototypical example, are the mainstays of analgesic therapy for the treatment of moderate to severe pain. Unfortunately, use of opioid analgesics is often associated with adverse effects on the GI tract, collectively termed opioid-induced bowel dysfunction (OBD). OBD includes symptoms such as constipation, decreased gastric emptying, abdominal pain and discomfort, bloating, nausea, and gastroesophageal reflux. Both central and peripheral opioid receptors are likely involved in the slowdown of gastrointestinal transit after opioid use. However, evidence suggests that peripheral opioid receptors in the GI tract are primarily responsible for the adverse effects of opioids on GI function.

Since the side effects of opioids are predominantly mediated by peripheral receptors, whereas the analgesia is central in origin, a peripherally selective antagonist can potentially block undesirable GI-related side effects without interfering with the beneficial central effects of analgesia or precipitating central nervous system withdrawal symptoms.

Of the three major opioid receptor subtypes, denoted mu, delta, and kappa, most clinically-used opioid analgesics are thought to act via mu opioid receptor activation to exert analgesia and to alter GI motility. Accordingly, peripherally selective mu opioid antagonists are expected to be useful for treating opioid-induced bowel dysfunction. Preferred agents will demonstrate significant binding to mu opioid receptors in vitro and be active in vivo in GI animal models.

Postoperative ileus (POI) is a disorder of reduced motility of the GI tract that occurs after abdominal or other surgery. The symptoms of POI are similar to those of OBD. Furthermore, since surgical patients are often treated during and after surgery with opioid analgesics, the duration of POI may be compounded by the reduced GI motility associated with opioid use. Mu opioid antagonists useful for treating OBD are therefore also expected to be beneficial in the treatment of POI.

SUMMARY OF THE INVENTION

The invention provides novel compounds that possess mu opioid receptor antagonist activity.

Accordingly, the invention provides a compound of formula (I):

wherein:

R¹ is —OR^(a) or —C(O)NR^(b)R^(c);

R² is selected from —NR^(a)C(O)R³, NR^(a)C(O)NHR⁵, NR^(a)S(O)₂R⁷, and —C(O)NR^(f)R⁸;

R³ is selected from C₁₋₆ alkyl optionally substituted with one or two substituents selected from R⁴, C₅₋₆cycloalkyl, and phenyl optionally substituted with —S(O)₂NR^(b)R^(c);

R⁴ is selected from —OR^(d), —C(O)NR^(b)R^(c), —NR^(b)R^(c), —C(O)OR^(d), —OC(O)R^(d), —S(O)₂R^(e), phenyl, and C₅₋₆cycloalkyl;

R⁵ is C₁₋₆ alkyl optionally substituted with one or two substituents selected from C₅₋₆cycloalkyl and phenyl optionally substituted with halo, or —S(O)₂R⁶;

R⁶ is C₁₋₆alkyl or phenyl;

R⁷ is C₁₋₆ alkyl optionally substituted with —S(O)₂R^(e) or phenyl optionally substituted with C₁₋₃alkyl;

R⁸ is C₁₋₆ alkyl optionally substituted with one or two substituents selected from R⁴, indolyl, and imidazolyl, or phenyl substituted with —S(O)₂NR^(b)R^(c);

R^(a), R^(b), R^(c), R^(d), and R^(f) are each independently hydrogen or C₁₋₃alkyl;

R^(e) is C₁₋₃alkyl;

m is 0, 1, or 2;

n is 0, 1, or 2;

R⁹ and R¹⁰ are each hydrogen, or R⁹ and R¹⁰ taken together form —CH₂—, provided that when R² is —C(O)NR^(f)R⁸, or when n is 0, R⁹ and R¹⁰ are each hydrogen; and

the dashed lines represent optional bonds;

or a pharmaceutically-acceptable salt thereof.

The invention also provides a pharmaceutical composition comprising a compound of the invention and a pharmaceutically-acceptable carrier.

The invention also provides a method of treating a disease or condition ameliorated by treatment with a mu opioid receptor antagonist, e.g. a disorder of reduced motility of the gastrointestinal tract such as opioid-induced bowel dysfunction and post-operative ileus, the method comprising administering to the mammal, a therapeutically effective amount of a compound or of a pharmaceutical composition of the invention.

The compounds of the invention can also be used as research tools, i.e. to study biological systems or samples, or for studying the activity of other chemical compounds. Accordingly, in another of its method aspects, the invention provides a method of using a compound of formula (I), or a pharmaceutically acceptable salt thereof, as a research tool for studying a biological system or sample or for discovering new compounds having mu opioid receptor activity, the method comprising contacting a biological system or sample with a compound of the invention and determining the effects caused by the compound on the biological system or sample.

In separate and distinct aspects, the invention also provides synthetic processes and intermediates described herein, which are useful for preparing compounds of the invention.

The invention also provides a compound of the invention as described herein for use in medical therapy, as well as the use of a compound of the invention in the manufacture of a formulation or medicament for treating a disease or condition ameliorated by treatment with a mu opioid receptor antagonist, e.g. a disorder of reduced motility of the gastrointestinal tract, in a mammal.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides 8-azabicyclo[3.2.1]octane mu opioid receptor antagonists of formula (I), or pharmaceutically-acceptable salts thereof. The following substituents and values are intended to provide representative examples of various aspects of this invention. These representative values are intended to further define such aspects and are not intended to exclude other values or limit the scope of the invention.

In a specific aspect of the invention, R¹ is —OR^(a) or —C(O)NR^(b)R^(c).

In another specific aspect, R¹ is —OH or —C(O)NH₂.

In yet another specific aspect, R¹ is —C(O)NH₂.

In a specific aspect, R² is selected from —NR^(a)C(O)R³, —NR^(a)C(O)NHR⁵, —NR^(a)S(O)₂R⁷, and —C(O)NR^(a)R⁸.

In another specific aspect, R² is —NR^(a)C(O)R³ wherein R³ is selected from C₁₋₆alkyl optionally substituted with one or two substituents selected from R⁴, C₅₋₆cycloalkyl, and phenyl optionally substituted with —S(O)₂NR^(b)R^(c).

In another specific aspect, R² is —NR^(a)C(O)R³ wherein R^(a) is hydrogen or methyl; and R³ is selected from C₁₋₄ alkyl optionally substituted with one substituent selected from —OH, —C(O)NH₂, —NH₂, —N(CH₃)₂, —C(O)OH, —OC(O)CH₃, —S(O)₂CH₃, and cyclohexyl, cyclohexyl, and phenyl optionally substituted with —S(O)₂NH₂.

In yet another specific aspect, R² is —NHC(O)CH₂OH or —N(CH₃) C(O)CH₂OH.

In a specific aspect, R² is —NR^(a)C(O)NHR⁵ wherein R⁵ is selected from C₁₋₆ alkyl optionally substituted with one or two substituents selected from C₅₋₆cycloalkyl and phenyl optionally substituted with halo, or —S(O)₂R⁶.

In another specific aspect, R² is —NR^(a)C(O)NHR⁵ wherein R^(a) is hydrogen or methyl; and R⁵ is C₁₋₄ alkyl optionally substituted with one substituent selected from cyclohexyl, phenyl, and 4-fluorophenyl, or —S(O)₂-phenyl.

In yet another specific aspect, R² is —NHC(O)NHCH₂-cyclohexyl.

In a specific aspect, R² is —NR^(a)S(O)₂R⁷ wherein R⁷ is C₁₋₆alkyl optionally substituted with —S(O)₂R^(e) or phenyl optionally substituted with C₁₋₃alkyl.

In another specific aspect R² is —NR^(a)S(O)₂R⁷ wherein R^(a) is hydrogen or methyl; and R⁷ is C₁₋₄ alkyl optionally substituted with —S(O)₂CH₃, or phenyl optionally substituted with methyl.

In yet another specific aspect R² is —NHS(O)₂CH₃ or —NHS(O)₂CH₂ S(O)₂CH₃.

In a specific aspect, R² is —C(O)NR^(f)R⁸ wherein R⁸ is C₁₋₆ alkyl optionally substituted with one or two substituents selected from R⁴, indolyl, and imidazolyl, or phenyl substituted with —S(O)₂NR^(b)R^(c);

In another specific aspect, R² is —C(O)NR^(f)R⁸ wherein R^(f) is hydrogen or methyl, and R⁸ is C₁₋₆ alkyl optionally substituted with one or two substituents selected from —OH, —C(O)NH₂, —NH₂, indolyl, and imidazolyl, or 4-S(O)₂NH₂-phenyl.

In yet another specific aspect, R² is —C(O)NH(CH₂)₂N(CH₃)₂.

In a specific aspect, R⁹ and R¹⁰ are each hydrogen.

In another specific aspect, R⁹ and R¹⁰ taken together form —CH₂— and n is 1.

In a specific aspect, R^(a), R^(b), R^(c), R^(d), and R^(f) are each independently hydrogen or C₁₋₃alkyl.

In another specific aspect, R^(a), R^(b), R^(c), R^(d), and R^(f) are each independently hydrogen or methyl.

In another specific aspect, R^(a), R^(b), R^(c), R^(d), and R^(f) are each hydrogen.

In a specific aspect, R^(e) is C₁₋₃alkyl.

In another specific aspect, R^(e) is methyl.

In a specific aspect, m is 0, 1, or 2.

In another specific aspect, m is 1.

In a specific aspect, n is 0, 1, or 2.

In another specific aspect, n is 1 or 2.

In specific aspects, m is 0 and n is 1; or m is 1 and n is 0.

In a specific aspect, the optional bonds represented by dashed lines are present, i.e. the cyclic moiety in formula (I) bearing the substituent R⁹ is phenyl.

In another specific aspect, the optional bonds represented by dashed lines are absent, i.e. the cyclic moiety in formula (I) bearing the substituent R⁹ is cyclohexyl.

In a specific aspect, the invention provides a compound of formula (I) wherein:

R¹ is —OH or —C(O)NH₂;

R² is selected from —NR^(a)C(O)R³, —NR^(a)C(O)NHR⁵, —NR^(a)S(O)₂R⁷, and —C(O)NR^(f)R⁸;

R³ is selected from C₁₋₄ alkyl optionally substituted with one substituent selected from —OH, —C(O)NH₂, —NH₂, —N(CH₃)₂, —C(O)OH, —OC(O)CH₃, —S(O)₂CH₃, and cyclohexyl, cyclohexyl, and phenyl optionally substituted with —S(O)₂NH₂;

R⁵ is C₁₋₄ alkyl optionally substituted with one substituent selected from cyclohexyl, phenyl, and 4-fluorophenyl, or —S(O)₂-phenyl;

R⁷ is C₁₋₄ alkyl optionally substituted with —S(O)₂CH₃, or phenyl optionally substituted with methyl;

R⁸ is C₁₋₆ alkyl optionally substituted with one or two substituents selected from —OH, —C(O)NH₂, —NH₂, indolyl, and imidazolyl, or 4-S(O)₂NH₂-phenyl;

R⁹ and R¹⁰ are each hydrogen;

R^(a) is hydrogen or methyl;

m is 0, 1, or 2;

n is 0, 1, or 2;

or a pharmaceutically-acceptable salt thereof.

The invention further provides the compounds of Examples 1-139 herein.

The chemical naming convention used herein is illustrated for the compound of Example 1:

which is cyclohexanecarboxylic acid {1-cyclohexylmethyl-2-[3-endo-(3-hydroxyphenyl)-8-azabicyclo[3.2.1]oct-8-yl]-ethyl}amide. Alternatively, using the IUPAC conventions as implemented in AutoNom software, (MDL Information Systems, GmbH, Frankfurt, Germany), the compound is denoted cyclohexanecarboxylic acid {1-cyclohexylmethyl-2-[(1R,3R,5S)-3-(3-hydroxyphenyl)-8-aza-bicyclo[3.2.1]oct-8-yl]-ethyl}amide. The names used herein therefore correspond to the IUPAC notation with the endo orientation of the substituted phenyl group with respect to the 8-azabicyclo[3.2.1]octane group indicated explicitly. All of the compounds of the invention are in the endo orientation. For convenience, as used herein, the term “8-azabicyclooctane” means 8-azabicyclo[3.2.1]octane.

In addition to the endo stereochemistry with respect to the bicyclo group, the compounds of the invention may contain a chiral center in the substituent R² and at the carbon atom bearing the substituent R². Accordingly, the invention includes racemic mixtures, pure stereoisomers, and stereoisomer-enriched mixtures of such isomers, unless otherwise indicated. When the stereochemistry of a compound is specified, including both the orientation with respect to the 8-azabicyclooctane group and the chirality in a substituent R², or at the carbon atom bearing the substituent R², it will be understood by those skilled in the art, that minor amounts of other stereoisomers may be present in the compositions of the invention unless otherwise indicated, provided that any utility of the composition as a whole is not eliminated by the presence of such other isomers.

DEFINITIONS

When describing the compounds, compositions and methods of the invention, the following terms have the following meanings, unless otherwise indicated.

The term “alkyl” means a monovalent saturated hydrocarbon group which may be linear or branched or combinations thereof. Unless otherwise defined, such alkyl groups typically contain from 1 to 10 carbon atoms. Representative alkyl groups include, by way of example, methyl, ethyl, n-propyl (n-Pr), isopropyl (i-Pr), n-butyl (n-Bu), sec-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, 2,2-dimethylpropyl, 2-methylbutyl, 3-methylbutyl, 2-ethylbutyl, 2,2-dimethylpentyl, 2-propylpentyl, and the like.

The term “cycloalkyl” means a monovalent saturated carbocyclic group which may be monocyclic or multicyclic. Unless otherwise defined, such cycloalkyl groups typically contain from 3 to 10 carbon atoms. Representative cycloalkyl groups include, by way of example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl (chexyl), cycloheptyl, cyclooctyl, adamantyl, and the like.

The term “compound” means a compound that was synthetically prepared or prepared in any other way, such as by in vivo metabolism.

The term “therapeutically effective amount” means an amount sufficient to effect treatment when administered to a patient in need of treatment.

The term “treatment” as used herein means the treatment of a disease, disorder, or medical condition in a patient, such as a mammal (particularly a human) which includes:

-   -   (a) preventing the disease, disorder, or medical condition from         occurring, i.e., prophylactic treatment of a patient;     -   (b) ameliorating the disease, disorder, or medical condition,         i.e., eliminating or causing regression of the disease,         disorder, or medical condition in a patient, including         counteracting the effects of other therapeutic agents;     -   (c) suppressing the disease, disorder, or medical condition,         i.e., slowing or arresting the development of the disease,         disorder, or medical condition in a patient; or     -   (d) alleviating the symptoms of the disease, disorder, or         medical condition in a patient.

The term “pharmaceutically-acceptable salt” means a salt prepared from an acid or base which is acceptable for administration to a patient, such as a mammal. Such salts can be derived from pharmaceutically-acceptable inorganic or organic acids and from pharmaceutically-acceptable bases. Typically, pharmaceutically-acceptable salts of compounds of the present invention are prepared from acids.

Salts derived from pharmaceutically-acceptable acids include, but are not limited to, acetic, adipic, benzenesulfonic, benzoic, camphorsulfonic, citric, ethanesulfonic, fumaric, gluconic, glutamic, glycolic, hydrobromic, hydrochloric, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, oxalic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic, xinafoic (1-hydroxy-2-naphthoic acid), naphthalene-1,5-disulfonic acid and the like.

The term “amino-protecting group” means a protecting group suitable for preventing undesired reactions at an amino nitrogen. Representative amino-protecting groups include, but are not limited to, formyl; acyl groups, for example alkanoyl groups, such as acetyl and tri-fluoroacetyl; alkoxycarbonyl groups, such as tert-butoxycarbonyl (Boc); arylmethoxycarbonyl groups, such as benzyloxycarbonyl (Cbz) and 9-fluorenylmethoxycarbonyl (Fmoc); arylmethyl groups, such as benzyl (Bn), trityl (Tr), and 1,1-di-(4′-methoxyphenyl)methyl; silyl groups, such as trimethylsilyl (TMS) and tert-butyldimethylsilyl (TBDMS); and the like.

General Synthetic Procedures

Compounds of the invention can be prepared from readily available starting materials using the following general methods and procedures. Although a particular aspect of the present invention is illustrated in the schemes below, those skilled in the art will recognize that all aspects of the present invention can be prepared using the methods described herein or by using other methods, reagents and starting materials known to those skilled in the art. It will also be appreciated that where typical or preferred process conditions (i.e., reaction temperatures, times, mole ratios of reactants, solvents, pressures, etc.) are given, other process conditions can also be used unless otherwise stated. Optimum reaction conditions may vary with the particular reactants or solvent used, but such conditions can be determined by one skilled in the art by routine optimization procedures.

Additionally, as will be apparent to those skilled in the art, conventional protecting groups may be necessary to prevent certain functional groups from undergoing undesired reactions. The choice of a suitable protecting group for a particular functional group, as well as suitable conditions for protection and deprotection, are well known in the art. For example, numerous protecting groups, and their introduction and removal, are described in T. W. Greene and G. M. Wuts, Protecting Groups in Organic Synthesis, Third Edition, Wiley, New York, 1999, and references cited therein.

In one method of synthesis, compounds of the invention in which R² takes the value —NR^(a)C(O)R³, —NR^(a)C(O)NHR⁵, or —NR^(a)S(O)₂R⁷ are prepared as illustrated in Scheme A1. (The substituents and variables shown in the following schemes have the definitions provided above unless otherwise indicated).

In reaction (i) of Scheme A1, R^(3a) represents R³ or a protected form of R³, and L represents a leaving group, such as chloro, or R^(3a)C(O)-L represents a carboxylic acid or a carboxylate salt. For example, to prepare a compound in which R³ is —CH₂OH, a useful reagent is acetoxyacetyl chloride, in which R^(3a) is —CH₂OC(O)CH₃ and L is chloro. When R^(3a) is a protected form of R³, the reaction also includes a deprotection step, which is not shown.

Optimal reaction conditions for reaction (i) of Scheme A1 may vary depending on the chemical properties of the reagent R^(3a)C(O)-L, as is well known to those skilled in the art. For example, when L is a halo leaving group, such as chloro, the reaction is typically conducted by contacting intermediate (II) with between about 1 and about 2 equivalents of a compound of formula R^(3a)C(O)-L in an inert diluent, such as dichloromethane. Optionally, the reaction is conducted in the presence of base, for example between about 1 and about 6 equivalents of base, such as N,N-diisopropylethylamine or triethylamine. Suitable inert diluents also include 1,1,2,2-tetrachloroethane, tetrahydrofuran, dimethylacetamide, and the like. The reaction is typically conducted at a temperature in the range of about −50° C. to about 30° C. for about a quarter hour to about 16 hours, or until the reaction is substantially complete.

When the reagent R^(3a)C(O)-L is a carboxylic acid or a carboxylate salt, the reaction is typically conducted by contacting intermediate (II) with between about 1 and about 5 equivalents of the acid R^(3a)C(O)OH or the carboxylate salt, for example, R^(3a)C(O)OLi, in an inert diluent, optionally in the presence of an excess of base, both as described above, and in the presence of between about 1 and about 6 equivalents of an activating agent such as N,N-carbonyl diimidazole (CDI), N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)uronium hexafluorophosphate (HATU) or 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC). The reaction is typically conducted at a temperature in the range of about 25° C. to about 100° C. for about 2 hours to about 16 hours, or until the reaction is substantially complete.

The preparation of urea compounds of formula (Ib) is illustrated in reaction (ii) of Scheme A1. The reaction is typically conducted by contacting intermediate (II) with between about 1 and about 2 equivalents of an isocyanate compound R⁵—N═C═O in the presence of between about 3 and about 6 equivalents of base, such as N,N-diisopropylethylamine. The reaction is typically conducted at ambient temperature for about an hour to about 16 hours, or until the reaction is substantially complete.

Reaction (iii) of Scheme A1 illustrates the preparation of sulfonamide compounds of formula (Ic). The reaction is typically conducted by contacting intermediate (II) with between about 1 and about 2 equivalents of a sulfonyl compound R⁷S(O)₂L′, where L′ represents a leaving group such as chloro, for example, R⁷S(O)₂L′ is methanesulfonyl chloride. The reaction is carried out under similar conditions to those described above for reaction (i) when L represents a halo leaving group. Optionally, the reaction includes between about 1 and about 2 equivalents of a base such as 1,4-diazabicyclo[2.2.2]-octane (DABCO).

In another method of synthesis, compounds of the invention in which R² takes the value —C(O)NR^(f)R⁸, are prepared as illustrated in Scheme A2.

Typically, the reaction is conducted by contacting intermediate (IId) with between about 1 and about 2 equivalents of the amine HNR^(f)R⁸ under the amide coupling conditions described above for reaction (i) of Scheme A where the reagent R^(3a)C(O)-L is a carboxylic acid.

General procedures for the preparation of an intermediate of formula (II) are illustrated in Scheme B1

where P¹ is an amino-protecting group.

In Scheme B1, an intermediate of formula (IV), is reductively N-alkylated by reaction with an aldehyde of formula (III) to provide a protected intermediate (not shown) which is deprotected by conventional means to provide intermediate (II). The reaction is typically conducted by contacting intermediate (IV) with between about 1 and about 2 equivalents of aldehyde (III) in a suitable inert diluent, such as dichloromethane, in the presence of between about 0.9 and about 2 equivalents of a reducing agent. The reaction is typically conducted at a temperature in the range of about 0° C. to ambient temperature for about a half hour to about 3 hours or until the reaction is substantially complete. Typical reducing agents include sodium triacetoxyborohydride, sodium borohydride, and sodium cyanoborohydride. The product (II) is isolated by conventional means.

Alternatively, an intermediate (II) could be prepared by a similar process using the carboxylic acid corresponding to intermediate (III) under typical amide coupling conditions as described, for example, in Preparation 7, below.

An exemplary process for the preparation of an intermediate of formula (IId) is shown in Scheme B2.

where P² represents a C₁₋₃alkyl or a hydroxy-protecting group. The reaction is typically conducted by contacting intermediate (IIId) with about 1 equivalent of the bicyclooctane intermediate (IV) in an inert diluent in the presence of an excess of base, for example between about 3 and about 5 equivalents of base, such as N,N-diisopropylethylamine or triethylamine. The reaction is typically conducted at a temperature between about 25 and about 75° C. for between about 3 hours and about 16 hours or until the reaction is substantially complete. An intermediate of formula (IId) in which R¹ is C(O)NH₂ can be prepared from an intermediate (IId) in which R¹ is —OH through triflate and nitrile intermediates by a procedure analogous to that of Scheme D following and further described in the Examples below.

Aldehydes of formula (III) are commercially available or can be prepared by oxidation of the corresponding alcohol or by reduction of a corresponding ester by conventional procedures. Intermediates of formula (IIId) are also commercially available or are readily prepared from commercial starting materials as exemplified below.

Intermediates of formula (IV) can be prepared from readily available starting materials. For example, one process for the preparation of intermediate (IV′) in which R¹ is hydroxy is illustrated in Scheme C.

where Bn denotes the amino-protecting group benzyl. Protected 8-azabicyclo[3.2.1]octanone 1 is typically obtained from commercial sources and it can be prepared by the reaction of 2,5-dimethoxy tetrahydrofuran with benzylamine and 1,3-acetonedicarboxylic acid in an acidic aqueous solution in the presence of a buffering agent as described in US 2005/0228014. (See also, U.S. Pat. No. 5,753,673).

First, intermediate 1 is added to a solution of between about 1 and about 2 equivalents of the Grignard reagent 3-methoxyphenyl magnesium bromide in an inert diluent. The reaction is typically conducted at a temperature of between about 0° C. and about 10° C. for between about 1 and about 3 hours or until the reaction is substantially complete. Transmetalation of the Grignard reagent from magnesium to cerium by reaction with an equivalent amount of cerous chloride prior to use is advantageous for obtaining a good yield of intermediate 2. The hydroxy substituent is eliminated from intermediate 2 by treatment with aqueous 6N HCl to provide the hydrochloride salt of intermediate 3. This reaction is typically conducted at a temperature of between about 50° C. and about 100° C. for between about 1 and about 3 hours or until the reaction is substantially complete.

Hydrogenation of intermediate 3 saturates the double bond of the alkene moiety and removes the benzyl protecting group to provide intermediate 4. Typically, the reaction is conducted by exposing the HCl salt of 3 dissolved in ethanol to a hydrogen atmosphere in the presence of a transition metal catalyst. Finally, the methyl group is removed from intermediate 4 by contacting a cooled solution of intermediate 4 in an inert diluent with between about 1 and about 2 equivalents of boron tribromide, hydrogen bromide, or boron trichloride. The reaction is typically conducted at a temperature of between about −80° C. and about 0° C. for between about 12 and about 36 hours or until the reaction is substantially complete. Intermediate (IV′) can be isolated by conventional procedures as a free base or as a hydrobromide salt. Crystallization of the hydrobromide salt provides intermediate (IV′) with high stereospecificity in the endo configuration (endo to exo ratio of greater than 99.1:0.8).

A process for preparing intermediate (IV″) in which the variable R¹ is —C(O)NH₂ uses the phenol intermediate (IV′) as a starting material as shown in Scheme D.

where -OTf represents trifluoromethane sulfonate (commonly triflate) and P² represents an amino-protecting group, such as Boc or tri-fluoroacetyl.

For example, when Boc is used as the protecting group, first, the phenol intermediate (IV′) is typically reacted with about 1 equivalent of di-tert-butyl dicarbonate (commonly Boc₂O) to provide the Boc-protected intermediate 5. The reactants are typically cooled to about 0° C. and then allowed to warm to ambient temperature over a period of between about 12 and about 24 hours. When tri-fluoroacetyl is used as the protecting group, typically (IV′) is reacted with about 2 equivalents of tri-fluoroacetyl anhydride to form the protected intermediate 5. Next, intermediate 5 in an inert diluent is contacted with a slight excess, for example about 1.1 equivalents of trifluoromethane sulfonyl chloride in the presence of between about 1 and about 2 equivalents of base to provide intermediate 6 which can be isolated by conventional procedures. Reaction of 6 with zinc cyanide in the presence of a transition metal catalyst, provides intermediate 7. This reaction is typically conducted at a temperature between about 60° C. and 120° C. under an inert atmosphere for about 2 to about 12 hours or until the reaction is substantially complete.

Finally, the nitrile intermediate 7 is hydrolyzed and deprotected to provide the carboxamide intermediate (IV″). Typically, in this reaction, when P² is Boc, intermediate 7 in an acidic solvent, for example trifluoroacetic acid, is contacted with between about 4 and about 6 equivalents of concentrated sulfuric acid. Typically the reaction is conducted in the temperature range of between about 50° C. and about 80° C. for about 8 to about 24 hours or until the reaction is substantially complete. The product is typically isolated in freebase form. When a tri-fluoroacetyl protecting group is used, the nitrile intermediate is first hydrolyzed to the carboxamide in concentrated sulfuric acid as described above. Quenching of the hydrolysis reaction by addition of base also removes the protecting group. The product is isolated as the freebase or as the hydrochloric acid salt.

Further details regarding specific reaction conditions and other procedures for preparing representative compounds of the invention or intermediates thereto are described in the examples below.

Accordingly, in a method aspect, the invention provides a process for preparing a compound of formula (I), or a salt thereof, the process comprising (a) reacting a compound of formula (II) with a compound of formula R^(3a)C(O)-L, R⁵—N═C═O, or R⁷S(O)₂-L′ or (b) reacting a compound of formula (IId) with a compound of formula HNR^(f)R⁸ to provide a compound of formula (I), or a salt thereof.

In an additional aspect, the invention provides a compound of formula (II) and a compound of formula (IId) wherein the variables R¹, R⁹, R¹⁰, n, and m take any of the values described in aspects of the invention disclosed above. In particular, the invention provides a compound of formula (II), wherein R¹ is —C(O)NH₂ and a compound of formula (IId) wherein R¹ is —C(O)NH₂.

Pharmaceutical Compositions

The 8-azabicyclooctane compounds of the invention are typically administered to a patient in the form of a pharmaceutical composition or formulation. Such pharmaceutical compositions may be administered to the patient by any acceptable route of administration including, but not limited to, oral, rectal, vaginal, nasal, inhaled, topical (including transdermal) and parenteral modes of administration.

Accordingly, in one of its compositions aspects, the invention is directed to a pharmaceutical composition comprising a pharmaceutically-acceptable carrier or excipient and a therapeutically effective amount of a compound of formula (I) or a pharmaceutically acceptable salt thereof. Optionally, such pharmaceutical compositions may contain other therapeutic and/or formulating agents if desired. When discussing compositions, the “compound of the invention” may also be referred to herein as the “active agent”. As used herein, the term “compound of the invention” is intended to include compounds of formula (I) as well as the species embodied in formulas (Ia), (Ib), (Ic), and (Id). “Compound of the invention” includes, in addition, pharmaceutically-acceptable salts and solvates of the compound unless otherwise indicated.

The pharmaceutical compositions of the invention typically contain a therapeutically effective amount of a compound of the present invention or a pharmaceutically-acceptable salt thereof. Typically, such pharmaceutical compositions will contain from about 0.1 to about 95% by weight of the active agent; preferably, from about 5 to about 70% by weight; and more preferably from about 10 to about 60% by weight of the active agent.

Any conventional carrier or excipient may be used in the pharmaceutical compositions of the invention. The choice of a particular carrier or excipient, or combinations of carriers or excipients, will depend on the mode of administration being used to treat a particular patient or type of medical condition or disease state. In this regard, the preparation of a suitable pharmaceutical composition for a particular mode of administration is well within the scope of those skilled in the pharmaceutical arts. Additionally, the carriers or excipients used in the pharmaceutical compositions of this invention are commercially-available. By way of further illustration, conventional formulation techniques are described in Remington: The Science and Practice of Pharmacy, 20^(th) Edition, Lippincott Williams & White, Baltimore, Md. (2000); and H. C. Ansel et al., Pharmaceutical Dosage Forms and Drug Delivery Systems, 7^(th) Edition, Lippincott Williams & White, Baltimore, Md. (1999).

Representative examples of materials which can serve as pharmaceutically acceptable carriers include, but are not limited to, the following: sugars, such as lactose, glucose and sucrose; starches, such as corn starch and potato starch; cellulose, such as microcrystalline cellulose, and its derivatives, such as sodium carboxymethyl cellulose, ethyl cellulose and cellulose acetate; powdered tragacanth; malt; gelatin; talc; excipients, such as cocoa butter and suppository waxes; oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil, olive oil, corn oil and soybean oil; glycols, such as propylene glycol; polyols, such as glycerin, sorbitol, mannitol and polyethylene glycol; esters, such as ethyl oleate and ethyl laurate; agar; buffering agents, such as magnesium hydroxide and aluminum hydroxide; alginic acid; pyrogen-free water; isotonic saline; Ringer's solution; ethyl alcohol; phosphate buffer solutions; and other non-toxic compatible substances employed in pharmaceutical compositions.

Pharmaceutical compositions are typically prepared by thoroughly and intimately mixing or blending the active agent with a pharmaceutically-acceptable carrier and one or more optional ingredients. The resulting uniformly blended mixture can then be shaped or loaded into tablets, capsules, pills and the like using conventional procedures and equipment.

The pharmaceutical compositions of the invention are preferably packaged in a unit dosage form. The term “unit dosage form” refers to a physically discrete unit suitable for dosing a patient, i.e., each unit containing a predetermined quantity of active agent calculated to produce the desired therapeutic effect either alone or in combination with one or more additional units. For example, such unit dosage forms may be capsules, tablets, pills, and the like, or unit packages suitable for parenteral administration.

In one embodiment, the pharmaceutical compositions of the invention are suitable for oral administration. Suitable pharmaceutical compositions for oral administration may be in the form of capsules, tablets, pills, lozenges, cachets, dragees, powders, granules; or as a solution or a suspension in an aqueous or non-aqueous liquid; or as an oil-in-water or water-in-oil liquid emulsion; or as an elixir or syrup; and the like; each containing a predetermined amount of a compound of the present invention as an active ingredient.

When intended for oral administration in a solid dosage form (i.e., as capsules, tablets, pills and the like), the pharmaceutical compositions of the invention will typically comprise the active agent and one or more pharmaceutically-acceptable carriers, such as sodium citrate or dicalcium phosphate. Optionally or alternatively, such solid dosage forms may also comprise: fillers or extenders, such as starches, microcrystalline cellulose, lactose, sucrose, glucose, mannitol, and/or silicic acid; binders, such as carboxymethylcellulose, alginates, gelatin, polyvinyl pyrrolidone, sucrose and/or acacia; humectants, such as glycerol; disintegrating agents, such as agar-agar, calcium carbonate, potato or tapioca starch, alginic acid, certain silicates, and/or sodium carbonate; solution retarding agents, such as paraffin; absorption accelerators, such as quaternary ammonium compounds; wetting agents, such as cetyl alcohol and/or glycerol monostearate; absorbents, such as kaolin and/or bentonite clay; lubricants, such as talc, calcium stearate, magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate, and/or mixtures thereof; coloring agents; and buffering agents.

Release agents, wetting agents, coating agents, sweetening, flavoring and perfuming agents, preservatives and antioxidants can also be present in the pharmaceutical compositions of the invention. Examples of pharmaceutically-acceptable antioxidants include: water-soluble antioxidants, such as ascorbic acid, cysteine hydrochloride, sodium bisulfate, sodium metabisulfate, sodium sulfite and the like; oil-soluble antioxidants, such as ascorbyl palmitate, butylated hydroxyanisole, butylated hydroxytoluene, lecithin, propyl gallate, alpha-tocopherol, and the like; and metal-chelating agents, such as citric acid, ethylenediamine tetraacetic acid, sorbitol, tartaric acid, phosphoric acid, and the like. Coating agents for tablets, capsules, pills and like, include those used for enteric coatings, such as cellulose acetate phthalate, polyvinyl acetate phthalate, hydroxypropyl methylcellulose phthalate, methacrylic acid-methacrylic acid ester copolymers, cellulose acetate trimellitate, carboxymethyl ethyl cellulose, hydroxypropyl methyl cellulose acetate succinate, and the like.

Pharmaceutical compositions of the invention may also be formulated to provide slow or controlled release of the active agent using, by way of example, hydroxypropyl methyl cellulose in varying proportions; or other polymer matrices, liposomes and/or microspheres. In addition, the pharmaceutical compositions of the invention may optionally contain opacifying agents and may be formulated so that they release the active ingredient only, or preferentially, in a certain portion of the gastrointestinal tract, optionally, in a delayed manner. Examples of embedding compositions which can be used include polymeric substances and waxes. The active agent can also be in micro-encapsulated form, if appropriate, with one or more of the above-described excipients.

Suitable liquid dosage forms for oral administration include, by way of illustration, pharmaceutically-acceptable emulsions, microemulsions, solutions, suspensions, syrups and elixirs. Liquid dosage forms typically comprise the active agent and an inert diluent, such as, for example, water or other solvents, solubilizing agents and emulsifiers, such as ethyl alcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzyl alcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, oils (esp., cottonseed, groundnut, corn, germ, olive, castor and sesame oils), glycerol, tetrahydrofuryl alcohol, polyethylene glycols and fatty acid esters of sorbitan, and mixtures thereof. Suspensions, in addition to the active ingredient, may contain suspending agents such as, for example, ethoxylated isostearyl alcohols, polyoxyethylene sorbitol and sorbitan esters, microcrystalline cellulose, aluminum metahydroxide, bentonite, agar-agar and tragacanth, and mixtures thereof.

The compounds of this invention can also be administered parenterally (e.g. by intravenous, subcutaneous, intramuscular or intraperitoneal injection). For parenteral administration, the active agent is typically admixed with a suitable vehicle for parenteral administration including, by way of example, sterile aqueous solutions, saline, low molecular weight alcohols such as propylene glycol, polyethylene glycol, vegetable oils, gelatin, fatty acid esters such as ethyl oleate, and the like. Parenteral formulations may also contain one or more anti-oxidants, solubilizers, stabilizers, preservatives, wetting agents, emulsifiers, buffering agents, or dispersing agents. These formulations may be rendered sterile by use of a sterile injectable medium, a sterilizing agent, filtration, irradiation, or heat.

Alternatively, the pharmaceutical compositions of the invention are formulated for administration by inhalation. Suitable pharmaceutical compositions for administration by inhalation will typically be in the form of an aerosol or a powder. Such compositions are generally administered using well-known delivery devices, such as a metered-dose inhaler, a dry powder inhaler, a nebulizer or a similar delivery device.

When administered by inhalation using a pressurized container, the pharmaceutical compositions of the invention will typically comprise the active ingredient and a suitable propellant, such as dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas. Additionally, the pharmaceutical composition may be in the form of a capsule or cartridge (made, for example, from gelatin) comprising a compound of the invention and a powder suitable for use in a powder inhaler. Suitable powder bases include, by way of example, lactose or starch.

The compounds of the invention can also be administered transdermally using known transdermal delivery systems and excipients. For example, the active agent can be admixed with permeation enhancers, such as propylene glycol, polyethylene glycol monolaurate, azacycloalkan-2-ones and the like, and incorporated into a patch or similar delivery system. Additional excipients including gelling agents, emulsifiers and buffers, may be used in such transdermal compositions if desired.

If desired, the compounds of this invention may be administered in combination with one or more other therapeutic agents. In this embodiment, a compound of this invention is either physically mixed with the other therapeutic agent to form a composition containing both agents; or each agent is present in separate and distinct compositions which are administered to the patient simultaneously or sequentially.

For example, a compound of formula I can be combined with second therapeutic agent using conventional procedures and equipment to form a composition comprising a compound of formula I and a second therapeutic agent. Additionally, the therapeutic agents may be combined with a pharmaceutically acceptable carrier to form a pharmaceutical composition comprising a compound of formula I, a second therapeutic agent and a pharmaceutically acceptable carrier. In this embodiment, the components of the composition are typically mixed or blended to create a physical mixture. The physical mixture is then administered in a therapeutically effective amount using any of the routes described herein. Alternatively, the therapeutic agents may remain separate and distinct before administration to the patient. In this embodiment, the agents are not physically mixed together before administration but are administered simultaneously or at separate times as separate compositions. Such compositions can be packaged separately or may be packaged together as a kit. The two therapeutic agents in the kit may be administered by the same route of administration or by different routes of administration.

Any therapeutic agent compatible with the compounds of the present invention may be used as the second therapeutic agent. In particular, prokinetic agents acting via mechanisms other than mu opioid receptor antagonism may be used in combination with the present compounds. For example, 5-HT₄ receptor agonists, such as tegaserod, renzapride, mosapride, prucalopride, 1-isopropyl-1H-indazole-3-carboxylic acid {(1S,3R,5R)-8-[2-(4-acetylpiperazin-1-yl)ethyl]-8-azabicyclo[3.2.1]oct-3-yl}amide, 1-isopropyl-2-oxo-1,2-dihydroquinoline-3-carboxylic acid {(1S,3R,5R)-8-[(R)-2-hydroxy-3-(methanesulfonyl-methyl-amino)propyl]-8-azabicyclo[3.2.1]oct-3-yl}amide, and 4-(4-{[(2-isopropyl-1H-benzoimidazole-4-carbonyl)amino]methyl}-piperidin-1-ylmethyl)piperidine-1-carboxylic acid methyl ester and pharmaceutically-acceptable salts thereof may be used as the second therapeutic agent.

Additional useful prokinetic agents and other agents for gastrointestinal disorders include, but are not limited to, 5-HT₃ receptor agonists (e.g. pumosetrag), 5-HT_(1A) receptor antagonists (e.g. AGI 001), alpha-2-delta ligands (e.g. PD-217014), chloride channel openers (e.g. lubiprostone), dopamine antagonists (e.g. itopride, metaclopramide, domperidone), GABA-B agonists (e.g. baclofen, AGI 006), kappa opioid agonists (e.g. asimadoline), muscarinic M₁ and M₂ antagonists (e.g. acotiamide), motilin agonists (e.g. mitemcinal), guanylate cyclase activators (e.g. MD-1100) and ghrelin agonists (e.g. Tzp 101, RC 1139).

In addition, the compounds of the invention can be combined with opioid therapeutic agents. Such opioid agents include, but are not limited to, morphine, pethidine, codeine, dihydrocodeine, oxycontin, oxycodone, hydrocodone, sufentanil, fentanyl, remifentanil, buprenorphine, methadone, and heroin.

Numerous additional examples of such therapeutic agents are known in the art and any such known therapeutic agents may be employed in combination with the compounds of this invention. Secondary agent(s), when included, are present in a therapeutically effective amount, i.e. in any amount that produces a therapeutically beneficial effect when co-administered with a compound of the invention. Suitable doses for the other therapeutic agents administered in combination with a compound of the invention are typically in the range of about 0.05 μg/day to about 100 mg/day.

Accordingly, the pharmaceutical compositions of the invention optionally include a second therapeutic agent as described above.

The following examples illustrate representative pharmaceutical compositions of the present invention:

Formulation Example A Hard Gelatin Capsules for Oral Administration

A compound of the invention (50 g), spray-dried lactose (200 g) and magnesium stearate (10 g) are thoroughly blended. The resulting composition is loaded into a hard gelatin capsule (260 mg of composition per capsule).

Formulation Example B Hard Gelatin Capsules for Oral Administration

A compound of the invention (20 mg), starch (89 mg), microcrystalline cellulose (89 mg), and magnesium stearate (2 mg) are thoroughly blended and then passed through a No. 45 mesh U.S. sieve. The resulting composition is loaded into a hard gelatin capsule (200 mg of composition per capsule).

Formulation Example C Gelatin Capsules for Oral Administration

A compound of the invention (10 mg), polyoxyethylene sorbitan monooleate (50 mg), and starch powder (250 mg) are thoroughly blended and then loaded into a gelatin capsule (310 mg of composition per capsule).

Formulation Example D Tablets for Oral Administration

A compound of the invention (5 mg), starch (50 mg), and microscrystalline cellulose (35 mg) are passed through a No. 45 mesh U.S. sieve and mixed thoroughly. A solution of polyvinylpyrrolidone (10 wt % in water, 4 mg) is mixed with the resulting powders, and this mixture is then passed through a No. 14 mesh U.S. sieve. The granules so produced are dried at 50-60° C. and passed through a No. 18 mesh U.S. sieve. Sodium carboxymethyl starch (4.5 mg), magnesium stearate (0.5 mg) and talc (1 mg), which have previously been passed through a No. 60 mesh U.S. sieve, are then added to the granules. After mixing, the mixture is compressed on a tablet machine to afford a tablet weighing 100 mg.

Formulation Example E Tablets for Oral Administration

A compound of the invention (25 mg), microcrystalline cellulose (400 mg), filmed silicon dioxide (10 mg), and stearic acid (5 mg) are thoroughly blended and then compressed to form tablets (440 mg of composition per tablet).

Formulation Example F Single-Scored Tablets for Oral Administration

A compound of the invention (15 mg), cornstarch (50 mg), croscarmellose sodium (25 mg), lactose (120 mg), and magnesium stearate (5 mg) are thoroughly blended and then compressed to form single-scored tablet (215 mg of compositions per tablet).

Formulation Example G Suspension for Oral Administration

The following ingredients are thoroughly mixed to form a suspension for oral administration containing 100 mg of active ingredient per 10 mL of suspension:

Ingredients Amount Compound of the invention 0.1 g Fumaric acid 0.5 g Sodium chloride 2.0 g Methyl paraben 0.15 g Propyl paraben 0.05 g Granulated sugar 25.5 g Sorbitol (70% solution) 12.85 g Veegum k (Vanderbilt Co.) 1.0 g Flavoring 0.035 mL Colorings 0.5 mg Distilled water q.s. to 100 mL

Formulation Example H Dry Powder Composition

A micronized compound of the invention (1 mg) is blended with lactose (25 mg) and then loaded into a gelatin inhalation cartridge. The contents of the cartridge are administered using a powder inhaler.

Formulation Example J Injectable Formulation

A compound of the invention (0.1 g) is blended with 0.1 M sodium citrate buffer solution (15 mL). The pH of the resulting solution is adjusted to pH 6 using 1 N aqueous hydrochloric acid or 1 N aqueous sodium hydroxide. Sterile normal saline in citrate buffer is then added to provide a total volume of 20 mL.

It will be understood that any form of the compounds of the invention, (i.e. free base, pharmaceutical salt, or solvate) that is suitable for the particular mode of administration, can be used in the pharmaceutical compositions discussed above.

Utility

The 8-azabicyclooctane compounds of the invention are antagonists at the mu opioid receptor and therefore are expected to be useful for treating medical conditions mediated by mu opioid receptors or associated with mu opioid receptor activity, i.e. medical, conditions which are ameliorated by treatment with a mu opioid receptor antagonist. In particular, the compounds of the invention are expected to be useful for treating adverse effects associated with use of opioid analgesics, i.e. symptoms such as constipation, decreased gastric emptying, abdominal pain, bloating, nausea, and gastroesophageal reflux, termed collectively opioid-induced bowel dysfunction. The mu opioid receptor antagonists of the invention are also expected to be useful for treating post-operative ileus, a disorder of reduced motility of the gastrointestinal tract that occurs after abdominal or other surgery. In addition, it has been suggested that mu opioid receptor antagonist compounds may be used for reversing opioid-induced nausea and vomiting. Further, those mu opioid receptor antagonists exhibiting some central penetration may be useful in the treatment of dependency on, or addiction to, narcotic drugs, alcohol, or gambling, or in preventing, treating, and/or ameliorating obesity.

Since compounds of the invention increase motility of the gastrointestinal (GI) tract in animal models, the compounds are expected to be useful for treating disorders of the GI tract caused by reduced motility in mammals, including humans. Such GI motility disorders include, by way of illustration, chronic constipation, constipation-predominant irritable bowel syndrome (C-IBS), diabetic and idiopathic gastroparesis, and functional dyspepsia.

In one aspect, therefore, the invention provides a method of increasing motility of the gastrointestinal tract in a mammal, the method comprising administering to the mammal a therapeutically effective amount of a pharmaceutical composition comprising a pharmaceutically-acceptable carrier and a compound of the invention.

When used to treat disorders of reduced motility of the GI tract or other conditions mediated by mu opioid receptors, the compounds of the invention will typically be administered orally in a single daily dose or in multiple doses per day, although other forms of administration may be used. For example, particularly when used to treat post-operative ileus, the compounds of the invention may be administered parenterally. The amount of active agent administered per dose or the total amount administered per day will typically be determined by a physician, in the light of the relevant circumstances, including the condition to be treated, the chosen route of administration, the actual compound administered and its relative activity, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the like.

Suitable doses for treating disorders of reduced motility of the GI tract or other disorders mediated by mu opioid receptors will range from about 0.0007 to about 20 mg/kg/day of active agent, including from about 0.0007 to about 1.4 mg/kg/day. For an average 70 kg human, this would amount to from about 0.05 to about 100 mg per day of active agent.

In one aspect of the invention, the compounds of the invention are used to treat opioid-induced bowel dysfunction. When used to treat opioid-induced bowel dysfunction, the compounds of the invention will typically be administered orally in a single daily dose or in multiple doses per day. Preferably, the dose for treating opioid-induced bowel dysfunction will range from about 0.05 to about 100 mg per day.

In another aspect of the invention, the compounds of the invention are used to treat post-operative ileus. When used to treat post-operative ileus, the compounds of the invention will typically be administered orally or intravenously in a single daily dose or in multiple doses per day. Preferably, the dose for treating post-operative ileus will range from about 0.05 to about 100 mg per day.

The invention also provides a method of treating a mammal having a disease or condition associated with mu opioid receptor activity, the method comprising administering to the mammal a therapeutically effective amount of a compound of the invention or of a pharmaceutical composition comprising a compound of the invention.

As described above, compounds of the invention are mu opioid receptor antagonists. The invention further provides, therefore, a method of antagonizing a mu opioid receptor in a mammal, the method comprising administering a compound of the invention to the mammal.

The mu opioid receptor antagonists of the invention are optionally administered in combination with another therapeutic agent or agents, in particular, in combination with prokinetic agents acting via non-mu opioid mechanisms. Accordingly, in another aspect, the methods and compositions of the invention further comprise a therapeutically effective amount of another prokinetic agent.

In addition, the compounds of the invention are also useful as research tools for investigating or studying biological systems or samples having mu opioid receptors, or for discovering new compounds having mu opioid receptor activity. Any suitable biological system or sample having mu opioid receptors may be employed in such studies which may be conducted either in vitro or in vivo. Representative biological systems or samples suitable for such studies include, but are not limited to, cells, cellular extracts, plasma membranes, tissue samples, mammals (such as mice, rats, guinea pigs, rabbits, dogs, pigs, etc.) and the like. The effects of contacting a biological system or sample comprising a mu opioid receptor with a compound of the invention are determined using conventional procedures and equipment, such as the radioligand binding assay and functional assay described herein or other functional assays known in the art. Such functional assays include, but are not limited to, ligand-mediated changes in intracellular cyclic adenosine monophosphate (cAMP), ligand-mediated changes in activity of the enzyme adenylyl cyclase, ligand-mediated changes in incorporation of analogs of guanosine triphosphate (GTP), such as [³⁵S]GTPγS (guanosine 5′-O-(γ-thio)triphosphate) or GTP-Eu, into isolated membranes via receptor catalyzed exchange of GTP analogs for GDP analogs, and ligand-mediated changes in free intracellular calcium ions. A suitable concentration of a compound of the invention for such studies typically ranges from about 1 nanomolar to about 500 nanomolar.

When using compounds of the invention as research tools for discovering new compounds have mu opioid receptor activity, binding or functional data for a test compound or a group of test compounds is compared to the mu opioid receptor binding or functional data for a compound of the invention to identify test compounds that have superior binding or functional activity, if any. This aspect of the invention includes, as separate embodiments, both the generation of comparison data (using the appropriate assays) and the analysis of the test data to identify test compounds of interest.

Among other properties, compounds of the invention have been found to exhibit potent binding to mu opioid receptors and little or no agonism in mu receptor functional assays. Therefore, the compounds of the invention are potent mu opioid receptor antagonists. Further, compounds of the invention have demonstrated predominantly peripheral activity as compared with central nervous system activity in animal models. Therefore, these compounds can be expected to reverse opioid-induced reductions in GI motility without interfering with the beneficial central effects of analgesia. These properties, as well as the utility of the compounds of the invention, can be demonstrated using various in vitro and in vivo assays well-known to those skilled in the art. Representative assays are described in further detail in the following examples.

EXAMPLES

The following synthetic and biological examples are offered to illustrate the invention, and are not to be construed in any way as limiting the scope of the invention. In the examples below, the following abbreviations have the following meanings unless otherwise indicated. Abbreviations not defined below have their generally accepted meanings.

Boc = tert-butoxycarbonyl (Boc)₂O = di-tert-butyl dicarbonate DABCO = 1,4-diazaobicylco[2,2,2]octane triethylenediamine DCM = dichloromethane DIPEA = N,N-diisopropylethylamine DMA = dimethylacetamide DMAP = dimethylaminopyridine DMF = N,N-dimethylformamide DMSO = dimethyl sulfoxide EtOAc = ethyl acetate EtOH = ethanol HATU = N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl) uronium hexafluorophosphate MeCN = acetonitrile MeOH = methanol MeTHF = 2-methyltetrahydrofuran MTBE = tert-butyl methyl ether PyBop = benzotriazol-1-yloxytripyrrolidino-phosphonium hexafluorophosphate TFA = trifluoroacetic acid THF = tetrahydrofuran

Reagents (including secondary amines) and solvents were purchased from commercial suppliers (Aldrich, Fluka, Sigma, etc.), and used without further purification. Reactions were run under nitrogen atmosphere, unless noted otherwise. Progress of reaction mixtures was monitored by thin layer chromatography (TLC), analytical high performance liquid chromatography (anal. HPLC), and mass spectrometry, the details of which are given below and separately in specific examples of reactions. Reaction, mixtures were worked up as described specifically in each reaction; commonly they were purified by extraction and other purification methods such as temperature-, and solvent-dependent crystallization, and precipitation. In addition, reaction mixtures were routinely purified by preparative HPLC: a general protocol is described below. Characterization of reaction products was routinely carried out by mass and ¹H-NMR spectrometry. For NMR measurement, samples were dissolved in deuterated solvent (CD₃OD, CDCl₃, or DMSO-d₆), and ¹H-NMR spectra were acquired with a Varian Gemini 2000 instrument (300 MHz) under standard observation conditions. Mass spectrometric identification of compounds was performed by an electrospray ionization method (ESMS) with an Applied Biosystems (Foster City, Calif.) model API 150 EX instrument or an Agilent (Palo Alto, Calif.) model 1100 LC/MSD instrument.

Preparation 1: Synthesis of 3-endo-(8-azabicyclo[3.2.1]oct-3-yl)-phenol a. Preparation of 8-benzyl-3-exo-(3-methoxyphenyl)-8-azabicyclo[3.2.1]octan-3-ol

To a 3 L-3-necked flask fitted with an overhead stirrer and flushed with dry nitrogen was added cerous chloride powder (88.2 g, 0.35 mol). The solid was diluted with anhydrous tetrahydrofuran (500 mL) and cooled to 0° C. To the suspension was added 1M 3-methoxyphenyl magnesium bromide in THF (360 mL, 0.36 mol) dropwise while the temperature was maintained below 10° C. The resulting solution was stirred at 0° C. for 1.5 hours. A solution of 8-benzyl-8-aza-bicyclo[3.2.1]octan-3-one (54.5 g, 0.25 mol) in tetrahydrofuran (50 mL) was then added dropwise, while maintaining the internal temperature below 5° C. The resulting solution was stirred at 0° C. for 2 hours. The reaction was quenched with 10% aqueous acetic acid (400 mL) and stirred for 30 minutes at room temperature. Saturated sodium chloride solution (400 mL) was then added and the resulting suspension was stirred at room temperature for 20 hours to allow complete crystallization of product as the acetate salt. The crystals were filtered and washed with cold water (200 mL) followed by isopropyl acetate (200 mL) and dried under vacuum to give the title intermediate as a white crystalline powder (91.1 g, 93% yield). (m/z): [M+H]⁺ calcd for C₂₁H₂₅NO₂ 324.20; found, 324.5.

b. Preparation of 8-benzyl-3-(3-methoxyphenyl)-8-azabicyclo[3.2.1]oct-2-ene

To a 1 L flask fitted with a magnetic stir bar was added 8-benzyl-3-exo-(3-methoxy-phenyl)-8-azabicyclo[3.2.1]octan-3-ol as the acetate salt (80.4 g, 0.209 mol) followed by 6M aqueous hydrochloride acid (300 mL). The reaction was heated to 70° C. for 2 hours. The stirring was stopped and the reaction was diluted with dichloromethane (200 mL). The mixture was transferred to a separatory funnel and the layers were mixed, then allowed to settle. The organic layer was removed and saved. The aqueous layer was extracted with dichloromethane (2×200 mL). The combined organic layers were washed with saturated aqueous sodium chloride solution (400 mL) and dried over anhydrous sodium sulfate (30 g). Solvent was removed in vacuo to give the hydrochloride salt of the title intermediate as a sticky yellow oil (65.4 g, 91% yield). (m/z): [M+H]⁺ calcd for C₂₁H₂₃NO 306.19. Found 306.3.

c. Preparation of 3-endo-(3-methoxyphenyl)-8-azabicyclo[3.2.1]octane

To a 1 L round-bottom flask containing of the product of the previous step (65.4 g, 0.191 mol) was added ethanol (300 mL). The mixture was stirred at room temperature until the intermediate was fully dissolved. To the solution was added palladium hydroxide (6.7 g, ˜10 wt %) as a solid, portionwise, with care. The reaction vessel was purged with dry nitrogen and hydrogen was introduced carefully via balloon and needle. The hydrogen was bubbled through the solution for 10 minutes, and the solution was allowed to stir overnight under a hydrogen atmosphere. When the reaction was complete by HPLC, the hydrogen was removed from the reaction mixture and the vessel was purged with dry nitrogen for 10 minutes. The reaction was then filtered through Celite (5 g), and the Celite cake was washed with ethanol (100 mL). The combined ethanol solution was evaporated in vacuo, and the resulting residue was dissolved in dichloromethane (400 mL). The organic layer was washed with 3N sodium hydroxide (300 mL). The layers were separated and the aqueous layer was extracted with dichloromethane (2×200 mL). Combined organic layers were washed with aqueous sodium chloride (300 mL) and dried over potassium carbonate (30 g). The drying agent was removed via filtration and solvent was removed in vacuo to give the title intermediate as a yellow oil (27.6 g, 66% yield). (m/z): [M+H]⁺ calcd for C₁₄H₁₉NO 218.16. Found 218.3.

d. Synthesis of 3-endo-(8-azabicyclo[3.2.1]oct-3-yl)-phenol

To a 1-L round bottom flask fitted with a magnetic stirbar and an addition funnel was added the product of the previous step (27.6 g, 0.127 mol) and dichloromethane (300 mL). The reaction was cooled in a dry ice/acetone bath to −78° C. To the cooled reaction was added boron tribromide (1M solution in dichloromethane, 152 mL, 0.152 mol). The reaction was permitted to warm slowly to room temperature over a period of 20 hours. The reaction was placed on an ice bath and methanol (100 mL) was carefully added to quench the reaction. The solvent was removed in vacuo to give a crunchy beige solid. The solid was redissolved in methanol (100 mL). The solvent was removed in vacuo to give a crunchy beige solid. The solid was redissolved again in methanol (100 mL). The solvent was removed in vacuo to give a crunchy beige solid which was then dried under vacuum for 2 hours. The dried solid was then suspended in ethanol (110 mL) and the solution was heated on an oil bath to 80° C. To the hot solution was added just enough methanol to dissolve all the solid material (72 mL). The solution was cooled slowly to room temperature, and white crystals of the hydrobromide salt of the title intermediate were allowed to form. The solution was then further cooled to −20° C. in the freezer for one hour. The crystallization was warmed to room temperature and the crystals were collected via filtration. The white crystals were washed with cold ethanol (35 mL) and dried under house vacuum to give the hydrobromide salt of the title intermediate as a white powder (19.5 g, 54% yield). The mother liquor was evaporated to give a crunchy beige solid. The solid was redissolved in ethanol (30 mL) and heated to 80° C. A clear brown solution formed. The solution was cooled to room temperature and then to −20° C. for one hour. Crystals were then collected via filtration, washed with cold ethanol (10 mL), and dried under vacuum to give a second crop of crystals (5.5 g, 15% yield). (m/z): [M+H]⁺ calcd for C₁₃H₁₇NO 204.14. Found, 204.4.

Preparation 2: Synthesis of 3-endo-(8-azabicyclo[3.2.1]oct-3-yl)-benzamide a. Preparation of 3-endo-(3-hydroxyphenyl)-8-azabicyclo[3.2.1]octane-8-carboxylic acid tert-butyl ester

To a 500 mL reaction flask containing the hydrobromide salt of 3-endo-(8-azabicyclo[3.2.1]oct-3-yl)-phenol (24.8 g, 0.087 mol) was added dichloromethane (200 mL) under a dry nitrogen atmosphere. The slurry was cooled to 0° C. To the slurry was then added N,N-diisopropylethylamine (22.75 mL, 0.13 mol) and di-tert-butyl dicarbonate (19.03 g, 0.087 mol) in one portion as a solid. The reaction was allowed to warm to room temperature over a period of 16 hours. When the reaction was complete by HPLC, the reaction mixture (now a clear light brown solution) was transferred to a separatory funnel and diluted with isopropyl acetate (200 mL). The organic mixture was washed with saturated aqueous sodium bicarbonate (300 mL). The organic layer was removed and the aqueous layer was extracted with isopropyl acetate (200 mL). The combined organic layers were washed with aqueous sodium chloride solution (300 mL), the layers were separated, and the organic layer was dried over anhydrous sodium sulfate (20 g). Solvent was removed in vacuo to afford the title intermediate as a white solid (27.1 g, >100% yield). (m/z): [M+H]⁺ calcd for C₁₈H₂₅NO₃ 304.19; found 304.3, 248.3 (parent—tert-butyl)

b. Preparation of 3-endo-(3-trifluoromethanesulfonyloxy-phenyl)-8-aza-bicyclo[3.2.1]octane-8-carboxylic acid tert-butyl ester

To a 500 mL reaction flask fitted with a magnetic stirbar and purged with dry nitrogen was added the product of the previous step (27.1 g, 0.089 mol) and dichloromethane (250 mL). The solution was cooled to 0° C. on an ice bath. To the cold solution was added triethylamine (12.4 mL, 0.097 mol) and trifluoromethane sulfonyl chloride (9.43 mL, 0.097 mol) dropwise while maintaining the internal temperature below 10° C. To this reaction was added solid 4-N,N-dimethylaminopyridine (0.544 g, 4.46 mmol) in one portion. The reaction was warmed to room temperature and stirred for 30 minutes. The final solution was transferred to a separatory funnel. The organic layer was washed with saturated aqueous sodium bicarbonate (200 mL) and saturated aqueous sodium chloride (200 mL). The organic layer was separated and dried over anhydrous sodium sulfate (20 g). Drying agent was removed via filtration and solvent was removed in vacuo to yield the title intermediate as a clear oil (38.4 g, 98% yield). (m/z): [M+H]⁺ calcd for C₁₉H₂₄F₃NO₅S 436.14. Found 436.2, 380.3 (parent—tert-butyl).

c. Preparation of 3-endo-(3-cyanophenyl)-8-aza-bicyclo[3.2.1]octane-8-carboxylic acid tert-butyl ester

To a 1 L round bottom flask fitted with a magnetic stirbar and purged with dry nitrogen was added the product of the previous step (38.4 g, 88.3 mmol) and dimethylformamide (320 mL). The solution was stirred for 5 minutes to dissolve all starting material, then degassed under vacuum. A dry nitrogen atmosphere was again introduced. To the degassed solution was added zinc cyanide (15.5 g, 132 mmol) and tetrakis(triphenylphosphine)palladium(0) (5.1 g, 4.41 mmol) together as solids in one portion. The reaction was again degassed under vacuum and a dry nitrogen atmosphere was introduced. The reaction was heated to 80° C. for 4 hours. The reaction was cooled to room temperature and diluted with isopropyl acetate (500 mL). The resulting cloudy solution was filtered through Celite (10 g). The resulting organic solution was washed with saturated aqueous sodium bicarbonate (400 mL) and saturated aqueous sodium chloride (400 mL). The organic layer was separated and dried over anhydrous sodium sulfate (30 g). Drying agent was removed via filtration and solvent was removed in vacuo to give crude title intermediate as waxy brown crystals (29.9 g, >100% yield). (m/z): [M+H]⁺ calcd for C₁₉H₂₄N₂O₂ 313.19; found 313.3, 257.3 (parent—tert-butyl).

d. Synthesis of 3-endo-(8-azabicyclo[3.2.1]oct-3-yl)-benzamide

To a 15 mL round bottom flask fitted with a magnetic stirbar and a reflux condenser was added 3-endo-(3-cyanophenyl)-8-aza-bicyclo[3.2.1]octane-8-carboxylic acid tert-butyl ester (500 mg, 1.60 mmol) as a solid followed by trifluoroacetic acid (4 mL). To the solution was added concentrated sulfuric acid (440 μL, 5.0 equiv.). The reaction was heated to 65° C. for 10 hours. The reaction was poured into a solution of saturated aqueous sodium chloride (70 mL) and transferred to a separatory funnel. The aqueous layer was washed with isopropyl acetate (50 mL) to remove residual triphenylphosphine oxide from the previous step. To the aqueous layer was added 3 N aqueous sodium hydroxide (15 mL) to adjust the pH to 14. The aqueous layer was extracted with tetrahydrofuran (2×50 mL). Combined organic layers were dried over anhydrous sodium sulfate (3 g). Drying agent was removed via filtration and the solvent was removed in vacuo to give the title compound as a crunchy, partially crystalline foam (300 mg, 79% yield). (m/z): [M+H]⁺ calcd for C₁₄H₁₈N₂O 231.15. Found 231.2.

Preparation 3 a. Preparation of 2-cyclohexyl-1-formylethyl)-carbamic acid tert-butyl ester

A solution of 2-cyclohexyl-1-hydroxymethylethyl-carbamic acid tert-butyl ester (1.0 g, 3.88 mmol) in N,N-diisopropylethylamine (2.71 mL, 15.5 mmol) and dichloromethane (15 mL) was cooled to −20° C. and a solution of sulfur trioxide-pyridine complex (2.47 g, 15.5 mmol) in dimethyl sulfoxide (15 mL) was added. The reaction mixture was stirred for 4 h and then allowed to warm to room temperature. To the reaction mixture was added dichloromethane (40 mL). The reaction mixture was washed with 1.0N HCl and with water. The organic layer was collected, dried over anhydrous sodium sulfate, filtered, and concentrated to give the title intermediate as an oil (900 mg) which was used without further purification.

b. Synthesis of 3-endo-[8-(2-amino-3-cyclohexylpropyl)-8-aza-bicyclo[3.2.1]oct-3-yl]phenol

To a solution of 3-endo-(8-azabicyclo[3.2.1]oct-3-yl)phenol hydrobromide (0.25 g, 0.88 mmol) and 2-cyclohexyl-1-formylethyl)carbamic acid tert-butyl ester (0.25 g, 0.97 mmol) in N,N-diisopropylethylamine (150 uL, 0.89 mol) and dichloromethane (10 mL) was added sodium triacetoxyborohydride (0.22 g, 0.10 mmol). The reaction mixture was stirred for 12 h. Trifluoroacetic acid (10 mL) was added and the reaction mixture was stirred for 3 h. To the reaction mixture was added water (15 mL). The aqueous layer was basified to pH=10 with 6.0 N NaOH. The product was extracted with ethyl acetate (20 mL). The organic layer was collected, dried over anhydrous sodium sulfate, filtered, and concentrated to give the title compound. (m/z): [M+H]⁺ calcd for C₂₂H₃₄N₂O, 343.27. Found 343.5.

c. Synthesis of 3-endo-[8-(2-amino-3-cyclohexylpropyl)-8-azabicyclo[3.2.1]oct-3-yl]benzamide

Following the procedure of step b using the 8-azbicyclooctane benzamide intermediate of Preparation 2, the title compound was prepared. (m/z): [M+H]⁺ calcd for C₂₃H₃₅N₃O, 370.28. Found 370.4.

Preparation 4

Following the procedure of Preparation 3, step b, using (1-formyl-2-phenylethyl)-carbamic acid tert-butyl ester and the appropriate 8-azabicyclooctane intermediate, the following compounds were prepared:

3-endo-[8-(2-amino-3-phenylpropyl)-8-azabicyclo[3.2.1]oct-3-yl]phenol (m/z): [M+H]⁺ calcd for C₂₂H₂₈N₂O, 337.22. Found 337.5.

3-endo-[8-(2-amino-3-phenylpropyl)-8-azabicyclo[3.2.1]oct-3-yl]benzamide (m/z): [M+H]⁺ calcd for C₂₃H₂₉N₃O, 364.23. Found 365.0.

Preparation 5: Synthesis of 3-endo-[8-(3-cyclohexyl-2-methylaminopropyl)-8-azabicyclo[3.2.1]oct-3-yl]benzamide a. Preparation of 2-tert-butoxycarbonylamino-3-cyclohexyl-propionic acid methyl ester

To a solution of 2-tert-butoxycarbonylamino-3-cyclohexyl-propionic acid (3.0 g, 11.1 mmol) and potassium carbonate (1.5 g, 11.1 mmol) in N,N-dimethylformamide (20 mL) was added methyl iodide (0.795 μL; 12.1 mmol). The reaction mixture was stirred at room temperature overnight. To the reaction mixture was added ethyl acetate (100 mL) and the solution was washed with water (3×100 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated to give the title intermediate as an oil (3.1 g) which was used directly in the next step.

b. Preparation of (2-cyclohexyl-1-formylethyl)methyl-carbamic acid tert-butyl ester

To a solution of 2-tert-butoxycarbonylamino-3-cyclohexyl-propionic acid methyl ester (3.1 g) and methyl iodide (1.45 mL, 22.0 mmol) in N,N-Dimethylformamide (20 mL) cooled to 0° C. was added dry sodium hydride (320 mg, 13.3 mmol) in three portions. The reaction was stirred at room temperature for 2 h. To the reaction mixture was carefully added methanol (10 mL) and then ethyl acetate (100 mL) and the solution was washed with water (3×100 mL). The organics were dried over anhydrous sodium sulfate, filtered, and concentrated to give an oil (3.2 g). The resulting oil was dissolved in toluene (50 mL) and cooled to −78° C. To the cooled solution, 1.0 N diisobutylaluminum hydride in toluene (16.5 mL, 16.5 mmol) was added dropwise over 15 min. The reaction mixture was stirred at −78° C. for 2 h. Methanol (10 mL) was carefully added and the reaction mixture was warmed to room temperature and washed with 10% acetic acid in water (2×100 mL) followed by brine (100 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated. The crude product was purified by flash column chromatography eluting with 10% ethyl acetate in hexanes to provide the title intermediate (2.0 g).

c. Synthesis of 3-endo-[8-(3-cyclohexyl-2-methylaminopropyl)-8-azabicyclo[3.2.1]oct-3-yl]benzamide

Following the procedure of Preparation 3, step b, using the intermediate of the previous step, the title compound was prepared. (m/z): [M+H]⁺ calcd for C₂₄H₃₇N₃O, 384.29. Found 384.3.

Preparation 6: Synthesis of 3-endo-[8-(2-methylamino-3-phenylpropyl)-8-aza-bicyclo[3.2.1]oct-3-yl]-benzamide

Following the procedure of Preparation 5, steps b and c, using reagent 2-tert-butoxycarbonylamino-3-phenylpropionic acid methyl ester, the title compound was prepared. (m/z): [M+H]⁺ calcd for C₂₄H₃₁N₃O, 378.25. Found 378.2.

Preparation 7: Synthesis of 3-endo-[8-(2-aminoindan-2-ylmethyl)-8-aza-bicyclo[3.2.1]oct-3-yl]-phenol a. Preparation of (2-aminoindan-2-yl)-[3-endo-(3-hydroxyphenyl)-8-aza-bicyclo[3.2.1]oct-8-yl]methanone

To a solution of 3-endo-(8-azabicyclo[3.2.1]oct-3-yl)-phenol hydrobromide (0.51 g, 1.8 mmol), N-Boc-2-aminoindane-2-carboxylic acid (0.50 g, 1.8 mmol), and N,N-diisopropylethylamine (941 μL, 5.4 mmol) in N,N-dimethylformamide (3.0 mL) was added N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)uranium hexafluorophosphate (HATU) (0.779 g, 2.1 mmol). The reaction mixture was stirred for 2 h at room temperature, diluted with ethyl acetate (30 mL) and washed with 1.0N HCl (3×30 mL). The organic layer was collected, dried over anhydrous sodium sulfate, filtered, and concentrated. The resulting solid was stirred in dichloromethane (3 mL) and trifluoroacetic acid (8 mL) for 1 h. The reaction mixture was concentrated. The resulting material was dissolved in water (10 mL) and basified to pH=10 with 6.0N NaOH. The product was extracted with ethyl acetate, dried over anhydrous sodium sulfate, filtered, and concentrated. The resulting solid was used in the next step without further purification. (m/z): [M+H]⁺ calcd for C₂₃H₂₆N₂O₂, 363.20; found 363.3.

b. Synthesis of 3-endo-[8-(2-aminoindan-2-ylmethyl)-8-aza-bicyclo[3.2.1]oct-3-yl]-phenol

To a solution of the product of the previous step in tetrahydrofuran (10 mL) was added 2.0 N borane dimethylsulfide complex in tetrahydrofuran (2.7 mL, 5.4 mmol). The reaction mixture was stirred at 55° C. for 2 h and cooled to room temperature. To the reaction mixture was carefully added methanol (10 mL). The reaction mixture was stirred for 15 min and concentrated. The crude oil was dissolved in methanol (5 mL) and 4.0 N HCl in dioxane (5 mL). The reaction mixture was concentrated and purified by preparative HPLC to give the title compound as the bis TFA salt (405 mg). (m/z): [M+H]⁺ calcd for C₂₃H₂₈N₂O, 349.22. Found 349.3.

Preparation 8: Synthesis of 3-endo-[8-(2-amino-4-phenylbutyl)-8-aza-bicyclo[3.2.1]oct-3-yl]-phenol

Following the procedure of Example 3 below, 2-tert-butoxycarbonylamino-4-phenyl-butyric acid was reacted with 3-endo-(8-azabicyclo[3.2.1]oct-3-yl)phenol hydrobromide to form the intermediate 2-amino-1-[3-endo-(3-hydroxyphenyl)-8-aza-bicyclo[3.2.1]oct-8-yl]-4-phenyl-butan-1-one, which was reduced according to the procedure of Preparation 7 step b to provide the title compound. (m/z): [M+H]⁺ calcd for C₂₃H₃₀N₂O, 351.24. Found 351.

Preparation 9: Synthesis of 3-endo-[8-(2-amino-4-cyclohexylbutyl)-8-aza-bicyclo[3.2.1]oct-3-yl]phenol a. Preparation of 3-cyclohexyl-1-formylpropyl)carbamic acid tert-butyl ester

To a solution of 2-amino-4-cyclohexyl-butyric acid ethyl ester hydrochloride (5.0 g; 0.02 mol) and triethylamine (2.78 mL; 0.02 mol) in dichloromethane (50 mL) was added dropwise a solution of di-tert-butyl dicarbonate (4.36 g; 0.02 mol) in dichloromethane (20 mL). The reaction mixture was stirred for 2 h and washed with 10% acetic acid in water (2×50 mL) followed by water (2×50 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated to give an oil.

To the solution of the resulting oil and ethanol (40 mL) was added in four portions sodium borohydride (740 mg, 0.02 mol) over 5 min. The reaction mixture was stirred at room temperature for 6 h. To the reaction mixture was added 10% acetic acid in water. The reaction mixture was stirred until hydrogen evolution ceased and then concentrated. The crude oil was dissolved with ethyl acetate (75 mL) and washed with water (2×75 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated.

To a solution of the crude product and N,N-diisopropylethylamine (14 mL; 0.08 mol) in dichloromethane (50 mL) was added a solution of pyridine sulfur trioxide complex (12.7 g; 0.08 mol) in dimethyl sulfoxide (50 mL) at −20° C. The reaction mixture was stirred for 2 h and diluted with ethyl acetate (150 mL). The reaction mixture was washed with 1.0N HCl (3×100 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated to give an oil (5.8 g) which was used in the next step without further purification.

b. Synthesis of 3-endo-[8-(2-amino-4-cyclohexylbutyl)-8-aza-bicyclo[3.2.1]oct-3-yl]-phenol

Following the procedure of Preparation 3 step b using the intermediate of the previous step, the crude title compound was prepared. The crude product was purified by preparative HPLC to give the title compound as the bis TFA salt. The resulting TFA salt was dissolved in 0.1N HCl (100 mL) and lyophilized to give the bis HCl salt. (m/z): [M+H]⁺ calcd for C₂₃H₃₆N₂O, 357.25. Found 357.3

Preparation 10 a. Preparation of (1-cyclohexyl-3-oxopropyl)carbamic acid tert-butyl ester

To a solution of (1-cyclohexyl-3-hydroxypropyl)carbamic acid tert-butyl ester (500 mg; 1.9 mmol) and N,N-diisopropylethylamine (1.35 mL; 7.8 mol) in dichloromethane (5 mL) was added a solution of pyridine sulfur trioxide complex (1.25 g; 7.8 mmol) in dimethyl sulfoxide (5 mL) at −20° C. The reaction mixture was stirred for 2 h and diluted with dichloromethane (20 mL). The reaction mixture was washed with 10% acetic acid in water (2×15 mL). The organic layer was dried over anhydrous sodium sulfate, filtered, and concentrated. The crude oil was used in the next step without further purification.

b. Synthesis of 3-endo-[8-(3-amino-3-cyclohexylpropyl)-8-azabicyclo[3.2.1]oct-3-yl]-phenol

Following the procedure of Preparation 3 step b, using the intermediate of the previous step, the title compound was prepared. (m/z): [M+H]⁺ calcd for C₂₂H₃₄N₂O, 343.27. Found 343.4

c. Synthesis of 3-endo-[8-(3-amino-3-cyclohexylpropyl)-8-azabicyclo[3.2.1]oct-3-yl]-benzamide

Following the procedure of Preparation 3 step b, using the intermediate of step a and the 8-azabicyclooctane benzamide intermediate, the title compound was prepared. (m/z): [M+H]⁺ calcd for C₂₃H₃₅N₃O, 370.28. Found 370.5

d. Synthesis of 3-endo-[8-(3-amino-3-phenylpropyl)-8-azabicyclo[3.2.1]oct-3-yl]benzamide

Using similar procedures, the title compound was prepared. (m/z): [M+H]⁺ calcd for C₂₃H₂₉N₃O, 364.23. Found 364.4.

Preparation 11: Synthesis of 2-benzyl-3-[3-endo-(3-carbamoylphenyl)-8-aza-bicyclo[3.2.1]oct-8-yl]-propionic acid ethyl ester a. Preparation of ethyl (phenylmethyl)propanedioic acid

To a solution of diethyl benzylmalonate (20.0 g, 80 mmol) in ethanol (500 mL) was added potassium hydroxide (4.7 g, 84 mmol) as pellets. The mixture was stirred at room temperature for 24 h, and concentrated to dryness in vacuo. The residue was dissolved in water (300 mL), transferred to a separatory funnel, and washed with ether (2×150 mL). The aqueous solution was acidified to pH˜2 by adding conc. HCl, and extracted with ether (2×400 mL). The organic layer was dried over MgSO₄, filtered and evaporated to dryness in vacuo, yielding the title compound as an oil residue (16.9 g, 95%) which was used without further purification.

b. Preparation of 2-benzyl-acrylic acid ethyl ester

The product of the previous step (10 g, 45 mmol) in a round bottomed flask was cooled in an ice bath and then diethylamine (4.8 mL) and 37% aqueous formaldehyde solution (4.8 mL) was added over 10 min with stirring. After stirring for 7 h, the mixture was diluted with water (100 mL), and extracted with ether (500 mL). The organic layer was washed with 2M HCl (300 mL), saturated sodium bicarbonate (300 mL), and brine solution, dried over MgSO₄, and evaporated to dryness, to provide the title compound as an oil (6.07 g, 71%). ¹H NMR (CD₃OD) δ (ppm) 7.15-7.08 (m, 3H), 7.07-7.05 (m, 2H), 6.07 (d, J=1.5 Hz, 1H), 5.41 (d, J=1.5 Hz, 1H), 4.06-3.99 (q, J=6.6 Hz, 2H), 3.50 (s, 2H), 1.14-1.07 (t, J=6.6 Hz, 2H).

c. Preparation of 2-benzyl-3-[3-endo-(3-hydroxyphenyl)-8-azabicyclo[3.2.1]oct-8-yl]-propionic acid

A solution of 2-benzyl-acrylic acid ethyl ester (1.77 g; 9.3 mmol), 3-endo-(8-aza-bicyclo[3.2.1]oct-3-yl)phenol hydrobromide (2.65 g, 9.3 mmol) and N,N-diisopropylethylamine (6.5 mL, 37.3 mmol) in ethanol (25 mL) was stirred overnight at 70° C. The reaction mixture was cooled to room temperature and concentrated. The reaction mixture was extracted with ethyl acetate and washed with saturated Na₂CO₃. The organic layer was collected, dried over anhydrous sodium sulfate, filtered, and concentrated. The crude product was purified by flash column chromatography eluting with dichloromethane and methanol to provide the title compound (2.8 g). (m/z): [M+H]⁺ calcd for C₂₅H₃₁NO₃, 394.23; found 394.3

e. Synthesis of 2-benzyl-3-[3-endo-(3-carbamoylphenyl)-8-aza-bicyclo[3.2.1]oct-8-yl]-propionic acid ethyl ester

To solution of the product of the previous step (2.8 g; 7.1 mmol) and triethylamine (1.1 mL; 7.9 mmol) in dichloromethane (20 mL) cooled to 0° C. was added dropwise trifluoromethanesulfonyl chloride (0.827 mL; 7.8 mmol). To the reaction mixture was added 4-dimethylaminopyridine (43 mg; 0.35 mmol). The reaction mixture was warmed to room temperature, stirred for 30 min, and washed with water (2×20 mL). The organic layer was collected, dried over anhydrous sodium sulfate, filtered, and concentrated.

The resulting crude oil was dissolved in N,N-dimethylformamide (30 mL) and purged thoroughly with nitrogen. To the reaction mixture was added zinc cyanide (1.25 g; 10.6 mmol; and tetrakis(triphenylphosphine)palladium(0) (0.411 g; 0.355 mmol). The reaction mixture was stirred at 85° C. for 3 h, cooled to room temperature and filtered through Celite. The product was extracted with ethyl acetate (50 mL) and washed with water (3×50 mL). The organic layer was collected, dried over anhydrous sodium sulfate, filtered, and concentrated.

To a solution of the resulting crude oil and potassium carbonate (240 mg, 1.7 mmol) in dimethyl sulfoxide (25 mL) was added 30% hydrogen peroxide (5.5 mL). The reaction mixture was stirred for 3 h, cooled to 0° C., and the reaction was quenched with Na₂S₂O₅ maintaining an internal temperature of 25° C. The mixture was basified to pH=6 with 6.0 N NaOH. The product was extracted with ethyl acetate (200 mL) and washed with water (100 mL). The organic layer was washed with saturated NaCl solution (2×100 mL). The organic layer was collected, dried over anhydrous sodium sulfate, filtered, and concentrated.

The crude oil was dissolved in ethanol (10 mL) and 10.0N NaOH (0.7 mL) and stirred overnight at room temperature. The reaction was concentrated and the product was purified by preparative HPLC to give the title compound as the TFA salt. (m/z): [M+H]⁺ calcd for C₂₄H₂₈N₂O₃, 393.21; found 393.2

Example 1 Synthesis of cyclohexanecarboxylic acid {1-cyclohexylmethyl-2-[3-endo-(3-hydroxyphenyl)-8-azabicyclo[3.2.1]oct-8-yl]-ethyl}amide

To a solution of 3-endo-[8-(2-amino-3-cyclohexylpropyl)-8-azabicyclo[3.2.1]oct-3-yl]phenol (20 mg, 0.058 mmol) and triethylamine (8.1 μL, 0.058 mmol) in dichloromethane (1.0 mL) was added cyclohexanecarbonyl chloride (7.9 μL, 0.058 mmol). The reaction mixture was stirred for 12 h, concentrated, and purified by preparative HPLC to give the title compound as the TFA salt (26.8 mg). (m/z): [M+H]⁺ calcd for C₂₉H₄₄N₂O₂, 453.27; found 453.4.

Example 2 Synthesis of N-{1-cyclohexylmethyl-2-[3-endo-(3-hydroxy-phenyl)-8-azabicyclo[3.2.1]oct-8-yl]ethyl}-2-hydroxyacetamide

To a solution of 3-endo-[8-(2-amino-3-cyclohexylpropyl)-8-aza-bicyclo[3.2.1]oct-3-yl]phenol (50 mg, 0.15 mmol), succinamic acid (7 mg, 0.06 mmol), and triethylamine (20 μL, 0.14 mmol) in dichloromethane (1.0 mL) was added acetoxyacetyl chloride (16 μL, 0.15 mmol). The reaction mixture was stirred for 30 min, concentrated and diluted with methanol (1 mL). To the reaction mixture was added 6.0N NaOH (150 μL). The reaction mixture was stirred overnight, concentrated, and purified by preparative HPLC to give the title compound as the TFA salt (11.3 mg). (m/z): [M+H]⁺ calcd for C₂₄H₃₆N₂O₃, 401.27; found 401.2.

Example 3 Synthesis of N-{1-cyclohexylmethyl-2-[3-endo-(3-hydroxy-phenyl)-8-azabicyclo[3.2.1]oct-8-yl]ethyl}succinamide

To a solution of 3-endo-[8-(2-amino-3-cyclohexylpropyl)-8-aza-bicyclo[3.2.1]oct-3-yl]phenol (20 mg, 0.060 mmol) and N,N-diisopropylethylamine (10 μL, 0.058 mmol) in N,N-dimethylformamide (1.0 mL) was added N,N,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)uranium hexafluorophosphate (33 mg, 0.087 mmol). The reaction mixture was stirred overnight, concentrated, and purified by preparative HPLC to give the title compound as the TFA salt (22.8 mg). (m/z): [M+H]⁺ calcd for C₂₆H₃₉N₃O₃, 442.30; found 442.2.

Example 4 Synthesis of 1-cyclohexylmethyl-3-{1-cyclohexylmethyl-2-[3-endo-(3-hydroxyphenyl)-8-azabicyclo[3.2.1]oct-8-yl]ethyl}urea

To a solution of 3-endo-[8-(2-amino-3-cyclohexylpropyl)-8-aza-bicyclo[3.2.1]oct-3-yl]phenol (50 mg, 0.15 mmol) and N,N-diisopropylethylamine (10 μL, 0.058 mmol) in acetonitrile (1.0 mL) was added cyclohexane methyl isoscyanate (8.3 μL, 0.058 mmol). The reaction mixture was stirred overnight at 50° C., concentrated, and purified by preparative HPLC to give the title compound as the TFA salt (20.5 mg). (m/z): [M+H]⁺ calcd for C₃₀H₄₇N₃O₂, 482.37; found 482.4.

Example 5 Synthesis of N-{1-cyclohexylmethyl-2-[3-endo-(3-hydroxy-phenyl)-8-azabicyclo[3.2.1]oct-8-yl]ethyl}4-methyl-benzenesulfonamide

To a solution of 3-endo-[8-(2-amino-3-cyclohexylpropyl)-8-aza-bicyclo[3.2.1]oct-3-yl]phenol (20 mg, 0.058 mmol) and triethylenediamine (6.5 mg, 0.058 mmol) in dichloromethane (1 mL) was added p-toluenesulfonyl chloride. The reaction mixture was stirred overnight, concentrated, and purified by preparative HPLC to give the title compound as the TFA salt (13.6 mg). (m/z): [M+H]⁺ calcd for C₂₉H₄₀N₂O₃S, 497.28; found 497.2.

Example 6 Synthesis of 3-endo-{8-[(S)-2-((S)-1-carbamoyl-3-methyl-butylcarbamoyl)-3-phenylpropyl]-8-azabicyclo[3.2.1]oct-3-yl}benzamide and 3-endo-{8-[(R)-2-((S)-1-carbamoyl-3-methylbutylcarbamoyl)-3-phenyl-propyl]-8-azabicyclo[3.2.1]oct-3-yl}benzamide

To a solution of 2-benzyl-3-[3-endo-(3-carbamoylphenyl)-8-aza-bicyclo[3.2.1]oct-8-yl]-propionic acid (30 mg; 0.058 mmol), (S)-2-amino-4-methylpentanoic acid amide hydrochloride (11.8 mg, 0.071 mmol), and N,N-diisopropylethylamine (20 μL, 0.115 mmol) in N,N-dimethylformamide (0.5 mL) was added N,N,N′,N′-tetramethyl-O-(7-azabenzotriazol-1-yl)uranium hexafluorophosphate (30 mg, 0.087 mmol). The reaction was stirred overnight. The reaction mixture was stirred overnight, concentrated, and the diastereomers (23.6 mg) were purified by preparative HPLC to give the title compounds as their TFA salts. (m/z): [M+H]⁺ calcd for C₃₀H₄₀N₄O₃, 505.31; found 505.2.

Examples 7 to 139

Using the intermediates of Preparations 1 to 11 and processes similar to those of Examples 1 to 6, the compounds of Tables 1 to 15 were prepared.

TABLE 1

Ex Calc. Obs. No R¹ R³ R^(a) Formula [M + H]⁺ [M + H]⁺  7 OH (CH₂)₂-chexyl H C₃₁H₄₈N₂O₂ 481.37 481.4  8 OH (CH₂)₂C(O)OH H C₂₆H₃₈N₂O₄ 443.28 443.2  9 OH phenyl H C₂₉H₃₈N₂O₂ 447.29 447.2 10 OH (CH₂)₂-phenyl H C₃₁H₄₂N₂O₂ 475.32 475.2 11 OH CH₂N(CH₃)₂ H C₂₆H₄₁N₃O₂ 428.32 428.2 12 OH CH₃ H C₂₄H₃₆N₂O₂ 385.28 385.2 13 OH 4-S(O)₂NH₂-phenyl H C₂₉H₃₉N₃O₄S 526.27 526.2 14 C(O)NH₂ chexyl H C₃₀H₄₅N₃O₂ 480.35 480.4 15 C(O)NH₂ (CH₂)₂-chexyl H C₃₂H₄₉N₃O₂ 508.38 508.4 16 C(O)NH₂ CH₂OH H C₂₅H₃₇N₃O₃ 428.28 428.2 17 C(O)NH₂ phenyl H C₃₀H₃₉N₃O₂ 474.30 474.2 18 C(O)NH₂ (CH₂)₂-phenyl H C₃₂H₄₃N₃O₂ 502.34 502.2 19 C(O)NH₂ CH₂-chexyl H C₃₁H₄₈N₄O₂ 509.38 509.4 20 C(O)NH₂ CH₂-phenyl H C₃₁H₄₂N₄O₂ 503.33 503.2 21 C(O)NH₂ (CH₂)₂—C(O)NH₂ H C₂₇H₄₀N₄O₃ 469.31 469.2 22 C(O)NH₂ CH₂OH CH₃ C₂₆H₃₉N₃O₃ 442.30 442.4 23 C(O)NH₂ (CH₂)₃C(O)OH CH₃ C₂₉H₄₃N₃O₄ 498.33 498.4 24 C(O)NH₂ CH₂S(O)₂CH₃ CH₃ C₂₇H₄₁N₃O₄S 504.28 504.4

TABLE 2

Ex Calc. Obs. No R¹ R⁵ Formula [M + H]⁺ [M + H]⁺ 25 OH CH₂-phenyl C₃₀H₄₁N₃O₂ 476.32 476.2 26 OH (CH₂)₄CH₃ C₂₈H₄₅N₃O₂ 456.35 456.2 27 C(O)NH₂ CH(CH₃)₂ C₂₈H₄₄N₄O₂ 469.35 469.4

TABLE 3

Ex Calc. Obs. No R¹ R³ R^(a) Formula [M + H]⁺ [M + H]⁺ 28 OH CH₂OH H C₂₄H₃₀N₂O₃ 395.23 395.3 29 OH chexyl H C₂₉H₃₈N₂O₂ 447.29 447.4 30 OH (CH₂)₂-chexyl H C₃₁H₄₂N₂O₂ 475.32 475.2 31 OH (CH₂)₂C(O)OH H C₂₆H₃₂N₂O₄ 437.24 437.2 32 OH phenyl H C₂₉H₃₂N₂O₂ 441.25 441.2 33 OH (CH₂)₂-phenyl H C₃₁H₃₆N₂O₂ 469.28 468.6 34 OH CH₂N(CH₃)₂ H C₂₆H₃₅N₃O₂ 422.27 422.2 35 OH CH₃ H C₂₄H₃₀N₂O₂ 379.23 379.2 36 OH (CH₂)₂C(O)NH₂ H C₂₆H₃₃N₃O₃ 436.25 436.2 37 OH 4-S(O)₂NH₂-phenyl H C₂₉H₃₃N₃O₄S 520.22 520.2 38 C(O)NH₂ (CH₂)₂-chexyl H C₃₂H₄₃N₃O₂ 502.34 502.2 39 C(O)NH₂ chexyl H C₃₀H₃₉N₃O₂ 474.30 474.2 40 C(O)NH₂ CH₂OH H C₂₅H₃₁N₃O₃ 422.24 422.2 41 C(O)NH₂ (CH₂)₂C(O)NH₂ H C₂₇H₃₄N₄O₃ 463.26 462.2 42 C(O)NH₂ phenyl H C₃₀H₃₃N₃O₂ 468.26 468.2 43 C(O)NH₂ (CH₂)₂-phenyl H C₃₂H₃₇N₃O₂ 496.29 496.2 44 C(O)NH₂ CH₂OH CH₃ C₂₆H₃₃N₃O₃ 436.25 436.2 46 C(O)NH₂ (CH₂)₃C(O)OH CH₃ C₂₉H₃₇N₃O₄ 492.28 492.2 47 C(O)NH₂ CH₂S(O)₂CH₃ CH₃ C₂₇H₃₅N₃O₄S 498.24 498.2

TABLE 4

Ex Calc. Obs No R¹ R³ R^(a) Formula [M + H]⁺ [M + H]⁺ 48 OH CH₂-chexyl H C₃₀H₄₁N₃O₂ 476.32 476.2 49 OH CH₂-phenyl H C₃₀H₃₅N₃O₂ 470.27 470.2 50 OH S(O)₂-phenyl H C₂₉H₃₃N₃O₄S 520.22 520.2 51 C(O)NH₂ CH₂-chexyl H C₃₁H₄₂N₄O₂ 503.33 503.2 52 C(O)NH₂ CH₂-phenyl H C₃₁H₃₆N₄O₂ 497.28 497.2 53 C(O)NH₂ CH(CH₃)₂ CH₃ C₂₈H₃₈N₄O₂ 463.30 463.4

TABLE 5

Ex Calc. Obs. No R¹ Q Formula [M + H]⁺ [M + H]⁺ 54 OH C(O)-phenyl C₃₀H₃₂N₂O₂ 453.25 453.2 55 OH C(O)(CH₂)₂- C₃₂H₃₆N₂O₂ 481.28 481.2 phenyl 56 OH C(O)-chexyl C₃₀H₃₈N₂O₂ 459.29 459.2 57 OH C(O)(CH₂)₂- C₃₂H₄₂N₂O₂ 487.32 487.3 chexyl 58 OH C(O)NHCH₂- C₃₁H₃₅N₃O₂ 482.27 482.2 phenyl 59 OH C(O)NHCH₂- C₃₁H₄₁N₃O₂ 488.32 488.2 chexyl 60 OH C(O)CH₂OH C₂₅H₃₀N₂O₃ 407.23 407.2 61 OH S(O)₂CH₃ C₂₄H₃₀N₂O₃S 427.20 457.2 62 OH S(O)₂-phenyl C₂₉H₃₂N₂O₃S 489.21 489.2

TABLE 6

Ex Calc. Obs. No R¹ R³ Formula [M + H]⁺ [M + H]⁺ 63 OH phenyl C₃₀H₄₀N₂O₂ 461.31 460.2 64 OH (CH₂)₂-phenyl C₃₂H₄₄N₂O₂ 489.34 489.2 65 OH chexyl C₃₀H₄₆N₂O₂ 467.36 467.4 66 OH (CH₂)₂-chexyl C₃₂H₅₀N₂O₂ 495.39 495.4 67 OH NHCH₂-phenyl C₃₁H₄₃N₃O₂ 490.34 490.2 68 OH NHCH₂-chexyl C₃₁H₄₉N₃O₂ 496.38 496.4 69 OH CH₂OH C₂₅H₃₈N₂O₃ 415.29 415.2 70 OH (CH₂)₂C(O)NH₂ C₂₇H₄₁N₃O₃ 456.32 456.2 71 OH (CH₂)₃N(CH₃)₂ C₂₉H₄₇N₃O₂ 470.37 470.4 72 OH CH₃ C₂₅H₃₈N₂O₂ 399.29 399.2

TABLE 7

Ex Calc. Obs. No R¹ R³ Formula [M + H]⁺ [M + H]⁺ 73 OH (CH₂)₂-phenyl C₃₂H₃₈N₂O₂ 483.29 483.2 74 OH chexyl C₃₀H₄₀N₂O₂ 461.31 461.2 75 OH (CH₂)₂-chexyl C₃₂H₄₄N₂O₂ 489.34 489.4 76 OH phenyl C₃₀H₃₄N₂O₂ 455.26 455.2 77 OH NHCH₂-phenyl C₃₁H₃₇N₃O₂ 484.29 484.2 78 OH NHCH₂-chexyl C₃₁H₄₃N₃O₂ 490.34 490.2 79 OH CH₂OC(O)CH₃ C₂₇H₃₄N₂O₄ 451.25 451.2 80 OH (CH₂)₂C(O)NH₂ C₂₇H₃₅N₃O₃ 450.27 450.2 81 OH (CH₂)₃N(CH₃)₂ C₂₉H₄₁N₃O₂ 464.32 464.2 82 OH CH₃ C₂₅H₃₂N₂O₂ 393.25 393.2

TABLE 8

Ex Calc Obs. No R¹ R³ Formula [M + H]⁺ [M + H]⁺ 83 OH phenyl C₂₉H₃₈N₂O₂ 447.29 447.2 84 OH (CH₂)₂-phenyl C₃₁H₄₂N₂O₂ 475.32 475.2 85 OH chexyl C₂₉H₄₄N₂O₂ 453.34 453.2 86 OH (CH₂)₂C(O)NH₂ C₂₆H₃₉N₃O₃ 442.30 442.2 87 OH (CH₂)₃N(CH₃)₂ C₂₈H₄₅N₃O₂ 456.35 456.2 88 OH NHCH₂-phenyl C₃₀H₄₁N₃O₂ 476.32 476.2 89 OH (CH₂)₂-chexyl C₃₁H₄₈N₂O₂ 481.37 481.4 90 OH NHCH₂-chexyl C₃₀H₄₇N₃O₂ 482.37 482.2 91 OH CH₃ C₂₄H₃₆N₂O₂ 385.28 385.2 92 C(O)NH₂ CH₂OH C₂₅H₃₇N₃O₃ 428.28 428.4 93 C(O)NH₂ NHCH₂-phenyl C₃₁H₄₂N₄O₂ 503.33 503.4 94 C(O)NH₂ NHCH₂-(4-F-phenyl) C₃₁H₄₁FN₄O₂ 521.32 521.4

TABLE 9

Ex Calc. Obs. No R¹ R³ Formula [M + H]⁺ [M + H]⁺  95 C(O)NH₂ CH₂OH C₂₅H₃₁N₃O₃ 422.24 422.2  96 C(O)NH₂ NHC(CH₃)₂ C₂₇H₃₆N₄O₂ 449.28 449.4  97 C(O)NH₂ (CH₂)₃C(O)OH C₂₈H₃₅N₃O₄ 478.26 478.4  98 C(O)NH₂ CH((S)-OH)CH₃ C₂₆H₃₃N₃O₃ 436.25 436.4  99 C(O)NH₂ CH((S)-OH)CH₃ C₂₆H₃₃N₃O₃ 436.25 436.2 100 C(O)NH₂ CH₂S(O)₂CH₃ C₂₆H₃₃N₃O₄S 484.22 484.2 * Denotes chiral center. Example 98 and 99 have opposite stereochemistry at this center.

TABLE 10

Ex Calc. Obs. No R¹ R⁷ Formula [M + H]⁺ [M + H]⁺ 101 OH CH₃ C₂₃H₃₆N₂O₃S 421.24 421.2 102 OH phenyl C₂₈H₃₈N₂O₃S 483.26 483.2 103 C(O)NH₂ CH₃ C₂₄H₃₇N₃O₃S 448.26 448.4

TABLE 11

Ex Calc. Obs. No R¹ R⁷ Formula [M + H]⁺ [M + H]⁺ 104 C(O)NH₂ CH₃ C₂₄H₃₁N₃O₃S 442.21 442.2 105 C(O)NH₂ CH₂S(O)₂CH₃ C₂₅H₃₃N₃O₅S₂ 520.19 520.2

TABLE 12

Ex Calc. Obs. No R¹ R⁷ R^(a) n Formula [M + H]⁺ [M + H]⁺ 106 OH CH₃ H 1 C₂₃H₃₆N₂O₃S 421.24 421.2 107 C(O)NH₂ CH₃ H 1 C₂₄H₃₇N₃O₃S 448.26 448.2 108 C(O)NH₂ phenyl H 1 C₂₉H₃₉N₃O₃S 510.27 510.2 109 OH CH₃ H 2 C₂₄H₃₈N₂O₃S 435.26 435.2 110 OH phenyl H 2 C₂₉H₄₀N₂O₃S 497.28 497.2 111 C(O)NH₂ CH₃ CH₃ 1 C₂₅H₃₉N₃O₃S 462.27 462.4 112 C(O)NH₂ CH₂S(O)₂CH₃ H 1 C₂₅H₃₉N₃O₅S₂ 526.23 526.2 113 C(O)NH₂ CH₂S(O)₂CH₃ CH₃ 1 C₂₆H₄₁N₃O₅S₂ 540.25 540.4

TABLE 13

Ex Calc. Obs. No R¹ R⁷ R^(a) n Formula [M + H]⁺ [M + H]⁺ 114 OH phenyl H 1 C₂₈H₃₂N₂O₃S 477.21 477.2 115 C(O)NH₂ CH₃ H 1 C₂₃H₃₀N₂O₃S 415.20 415.2 116 C(O)NH₂ phenyl H 1 C₂₄H₃₁N₃O₃S 442.21 442.2 117 OH CH₃ H 2 C₂₄H₃₂N₂O₃S 429.21 429.2 118 OH phenyl H 2 C₂₉H₃₄N₂O₃S 491.23 491.2 119 C(O)NH₂ CH₃ CH₃ 1 C₂₅H₃₃N₃O₃S 456.22 456.2 120 C(O)NH₂ CH₂S(O)₂CH₃ H 1 C₂₅H₃₃N₃O₅S₂ 520.19 520.2 121 C(O)NH₂ CH₂S(O)₂CH₃ CH₃ 1 C₂₆H₃₅N₃O₅S₂ 534.20 534.2

TABLE 14

Ex Calc. Obs. No R Formula [M + H]⁺ [M + H]⁺ 122 CH₂-phenyl C₃₃H₃₈N₄O₃ 539.29 539.2 123 CH₂-indol-2-yl C₃₅H₃₉N₅O₃ 578.31 578.2 124 CH₃ C₂₇H₃₄N₄O₃ 463.26 463.4 125 CH((R)-OH)CH₃ C₂₈H₃₆N₄O₄ 493.27 493.4 126 CH₂-chexyl C₃₃H₄₄N₄O₃ 545.34 545.4 127 CH₂OH C₂₇H₃₄N₄O₄ 479.26 479.2 128 CH₂-imidazol-2-yl C₃₀H₃N₆O₃ 529.29 529.2 129 CH₂C(O)NH₂ C₂₈H₃₅N₅O₄ 506.27 506.2 130 (CH₂)₂C(O)OH C₂₉H₃₆N₄O₅ 521.27 521.2 * Denotes a chiral center. Both the (R) and (S) diastereomers were preprared.

TABLE 15

Ex Calc. Obs. No R⁸ R^(f) Formula [M + H]⁺ [M + H]⁺ 131 CH₂C(O)NH₂ H C₂₆H₃₂N₄O₃ 449.25 449.2 132 CH₂C(O)N(CH₃)₂ H C₂₈H₃₆N₄O₃ 477.28 477.2 133 (CH₂)₂OH H C₂₆H₃₃N₃O₃ 436.26 436.2 134 (CH₂)₂C(O)NH₂ H C₂₇H₃₄N₄O₃ 463.26 463.2 135 4-S(O)₂NH₂-phenyl H C₃₀H₃₄N₄O₄S 547.23 547.2 136 (CH₂)₂N(CH₃)₂ H C₂₈H₃₈N₄O₂ 463.30 463.2 137 (CH₂)₄N(CH₃)₂ H C₃₀H₄₂N₄O₂ 491.33 491.2 138 (CH₂)₆NH₂ H C₃₀H₄₂N₄O₂ 491.33 491.2 139 (CH₂)₂OH CH₃ C₂₇H₃₅N₃O₃ 450.27 450.4

Assay 1: Radioligand Binding Assay on Human Mu, Human Delta and Guinea Pig Kappa Opioid Receptors

a. Membrane Preparation

CHO-K1 (Chinese Hamster Ovary) cells stably transfected with human mu opioid or with guinea pig kappa receptor cDNA were grown in medium consisting of Ham's-F12 media supplemented with 10% FBS, 100 units/ml penicillin −100 μg/mL streptomycin and 800 μg/mL Geneticin in a 5% CO₂, humidified incubator @ 37° C. Receptor expression levels (B_(max)˜2.0 and ˜0.414 pmol/mg protein, respectively) were determined using [³H]-Diprenorphine (specific activity ˜50-55 Ci/mmol) in a membrane radioligand binding assay.

Cells were grown to 80-95% confluency (<25 subculture passages). For cell line passaging, the cell monolayer was incubated for 5 minutes at room temperature and harvested by mechanical agitation in 10 mL of PBS supplemented with 5 mM EDTA. Following resuspension, cells were transferred to 40 mL fresh growth media for centrifugation for 5 minutes at 1000 rpm and resuspended in fresh growth medium at the appropriate split ratio.

For membrane preparation, cells were harvested by gentle mechanical agitation with 5 mM EDTA in PBS followed by centrifugation (2500 g for 5 minutes). The pellets were resuspended in Assay Buffer (50 mM 4-(2-hydroxyethyl)piperazine-1-ethanesulfonic acid N-(2-hydroxyethyl)piperazine-N′-(2-ethanesulfonic acid) (HEPES)), pH 7.4, and homogenized with a polytron disrupter on ice. The resultant homogenates were centrifuged (1200 g for 5 minutes), the pellets discarded and the supernatant centrifuged (40,000 g for 20 minutes). The pellets were washed once by resuspension in Assay Buffer, followed by an additional centrifugation (40,000 g for 20 minutes). The final pellets were resuspended in Assay Buffer (equivalent 1 T-225 flask/1 mL assay buffer). Protein concentration was determined using a Bio-Rad Bradford Protein Assay kit and membranes were stored in frozen aliquots at −80° C., until required.

Human delta opioid receptor (hDOP) membranes were purchased from Perkin Elmer. The reported K_(d) and B_(max) for these membranes determined by saturation analyses in a [³H]—Natrindole radioligand binding assays were 0.14 nM (pK_(d)=9.85) and 2.2 pmol/mg protein, respectively. Protein concentration was determined using a Bio-Rad Bradford Protein Assay kit. Membranes were stored in frozen aliquots at −80° C., until required.

b. Radioligand Binding Assays

Radioligand binding assays were performed in an Axygen 1.1 mL deep well 96-well polypropylene assay plate in a total assay volume of 200 μL containing the appropriate amount of membrane protein (˜3, ˜2 and ˜20 μg for mu, delta and kappa, respectively) in Assay Buffer, supplemented with 0.025% bovine serum albumin (BSA). Saturation binding studies for determination of K_(d) values of the radioligand were performed using [³H]-Diprenorphine at 8-12 different concentrations ranging from 0.001 nM-5 nM. Displacement assays for determination of pKi values of compounds were performed with [³H]-Diprenorphine at 0.5, 1.2, and 0.7 nM for mu, delta, and kappa, respectively, and eleven concentrations of compound ranging from 10 pM-100 μM.

Binding data were analyzed by nonlinear regression analysis with the GraphPad Prism Software package (GraphPad Software, Inc., San Diego, Calif.) using the 3-parameter model for one-site competition. The curve minimum was fixed to the value for nonspecific binding, as determined in the presence of 10 μM naloxone. K_(i) values for test compounds were calculated, in Prism, from the best fit IC₅₀ values, and the K_(d) value of the radioligand, using the Cheng-Prusoff equation (K_(i)=IC₅₀/(1+([L]/K_(d))) where [L]=the concentration of [³H]-Diprenorphine. Results are expressed as the negative decadic logarithm of the K_(i) values, pK_(i).

Test compounds having a higher pK_(i) value in these assays have a higher binding affinity for the mu, delta, or kappa opioid receptor. The compounds of Examples 1-139 were tested in these assays. All of the compounds had a pK_(i) value between about 8.5 and about 10.2 at the human mu opioid receptor. For example, the compounds of Examples 1 through 6 had pK_(i) values of 10.2, 10.2, 9.9, 10.0, 9.1, and 10.2, respectively. Compounds of the invention also exhibited pK_(i) values between about 6.8 and about 10.3 human delta opioid receptor and between about 8.4 and about 11.3 at the guinea pig kappa opioid receptor.

Assay 2: Agonist Mediated Activation of the Mu-Opioid Receptor in Membranes Prepared from CHO-K1 Cells Expressing the Human mu-Opioid Receptor

In this assay, the potency and intrinsic activity values of test compounds were determined by measuring the amount of bound GTP-Eu present following receptor activation in membranes prepared from CHO-K1 cells expressing the human mu opioid receptor.

a. Mu Opioid Receptor Membrane Preparation:

Human mu opioid receptor (hMOP) membranes were either prepared as described above or were purchased from Perkin Elmer. The reported pK_(d) and B_(max) for the purchased membranes determined by saturation analyses in a [³H]-Diprenorphine radioligand binding assays was 10.06 and 2.4 pmol/mg protein, respectively. Protein concentration was determined using a Bio-Rad Bradford Protein Assay kit. Membranes were stored in frozen aliquots at −80° C., until required. Lyophilized GTP-Eu and GDP were diluted to 10 μM and 2 mM, respectively, in double distilled H₂O then mixed and permitted to sit at room temperature for 30 minutes prior to transfer to individual aliquots samples for storage at −20° C.

b. Human mu GTP-Eu Nucleotide Exchange Assay

GTP-Eu nucleotide exchange assays were performed using the DELPHIA GTP-binding kit (Perkin/Elmer) in AcroWell 96 well filter plates according to the manufacturer's specifications. Membranes were prepared as described above, and prior to the start of the assay, aliquots were diluted to a concentration of 200 μg/mL in Assay Buffer (50 mM HEPES, pH 7.4 at 25° C.), then homogenized for 10 seconds using a Polytron homogenizer. Test compounds were received as 10 mM stock solutions in DMSO, diluted to 400 μM into Assay Buffer containing 0.1% BSA, and serial (1:5) dilutions then made to generate ten concentrations of compound ranging from 40 pM-80 μM—GDP and GTP-Eu were diluted to 4 μM and 40 nM, respectively, in Assay Buffer. The assay was performed in a total volume of 100 μL containing 5 μg of membrane protein, test compound ranging from 10 pM-20 μM), 1 μM GDP, and 10 nM GTP-Eu diluted in 10 mM MgCl₂, 50 mM NaCl, and 0.0125% BSA, (final assay concentrations). A DAMGO (Tyr-D-Ala-Gly-(methyl)Phe-Gly-ol) concentration-response curve (ranging from 12.8 pM-1 μM) was included on every plate.

Assay plates were prepared immediately prior to assay following the addition of 25 μL of Assay Buffer, 25 μL of test compound, and 25 μL GDP and GTP-Eu. The assay was initiated by the addition of 25 μL membrane protein and allowed to incubate for 30 minutes. The assay plates were then filtered with a Waters vacuum manifold connected to the house vacuum regulated to 10-12 in. Hg and washed with room temperature GTP Wash Solution (2×300 mL). The bottoms of the plates were blotted to remove excess liquid. The plates were then immediately read to determine the amount of bound GTP-Eu by measuring Time Resolved Fluorescence (TRF) on a Packard Fusion Plate ReaderVehicle: DMSO not to exceed 1% final assay concentration.

The amount of bound GTP-Eu is proportional to the degree of activation of the mu opioid receptors by the test compound. The intrinsic activity (IA), expressed as a percentage, was determined as the ratio of the amount of bound GTP-Eu observed for activation by the test compound to the amount observed for activation by DAMGO which is presumed to be a full agonist (IA=100). With the exception of the compounds of Examples 76 and 104, the compounds of Examples 1 to 139 demonstrated intrinsic activities in this assay of less than about 30. For example, the compounds of Examples 1 through 6 had IA values of −9, 24, 3, −3, 2, and −7, respectively. Thus, the compounds of the present invention have been shown to act as antagonists at the human mu opioid receptor.

While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto. Additionally, all publications, patents, and patent documents cited hereinabove are incorporated by reference herein in full, as though individually incorporated by reference. 

1. A compound of formula (I):

wherein: R¹ is —OR^(a) or —C(O)NR^(b)R^(c); R² is selected from —NR^(a)C(O)R³, —NR^(a)C(O)NHR⁵, —NR^(a)S(O)₂R⁷, and —C(O)NR^(f)R⁸; R³ is selected from C₁₋₆ alkyl optionally substituted with one or two substituents selected from R⁴, C₅₋₆cycloalkyl, and phenyl optionally substituted with —S(O)₂NR^(b)R^(c); R⁴ is selected from —OR^(d), —C(O)NR^(b)R^(c), —NR^(b)R^(c), —C(O)OR^(d), —OC(O)R^(d), —S(O)₂R^(e), phenyl, and C₅₋₆cycloalkyl; R⁵ is C₁₋₆ alkyl optionally substituted with one or two substituents selected from C₅₋₆cycloalkyl and phenyl optionally substituted with halo, or —S(O)₂R⁶; R⁶ is C₁₋₆alkyl or phenyl; R⁷ is C₁₋₆ alkyl optionally substituted with —S(O)₂R^(e) or phenyl optionally substituted with C₁₋₃alkyl; R⁸ is C₁₋₆ alkyl optionally substituted with one or two substituents selected from R⁴, indolyl, and imidazolyl, or phenyl substituted with —S(O)₂NR^(b)R^(c); R^(a), R^(b), R^(c), R^(d), and R^(f) are each independently hydrogen or C₁₋₃alkyl; R^(e) is C₁₋₃alkyl; m is 0, 1, or 2; n is 0, 1, or 2; R⁹ and R¹⁰ are each hydrogen, or R⁹ and R¹⁰ taken together form —CH₂—, provided that when R² is —C(O)NR^(f)R⁸, or when n is 0, R⁹ and R¹⁰ are each hydrogen; and the dashed lines represent optional bonds; or a pharmaceutically-acceptable salt thereof.
 2. The compound of claim 1 wherein R¹ is —OH or —C(O)NH₂.
 3. The compound of claim 2 wherein: R³ is selected from C₁₋₄ alkyl optionally substituted with one substituent selected from —OH, —C(O)NH₂, —NH₂, —N(CH₃)₂, —C(O)OH, —OC(O)CH₃, —S(O)₂CH₃, and cyclohexyl, cyclohexyl, and phenyl optionally substituted with —S(O)₂NH₂; R⁵ is C₁₋₄ alkyl optionally substituted with one substituent selected from cyclohexyl, phenyl, and 4-fluorophenyl, or —S(O)₂-phenyl; R⁷ is C₁₋₄ alkyl optionally substituted with —S(O)₂CH₃, or phenyl optionally substituted with methyl; R⁸ is C₁₋₆ alkyl optionally substituted with one or two substituents selected from —OH, —C(O)NH₂, —NH₂, indolyl, and imidazolyl, or 4-S(O)₂NH₂-phenyl; R⁹ and R¹⁰ are each hydrogen; and R^(a) is hydrogen or methyl.
 4. The compound of claim 1 wherein the optional bonds on the cyclic moiety bearing the substituent R⁹ are present.
 5. The compound of claim 1 wherein the optional bonds on the cyclic moiety bearing the substituent R⁹ are absent.
 6. The compound of claim 1 wherein R² is —NR^(a)C(O)R³.
 7. The compound of claim 1 wherein R² is —NR^(a)C(O)NHR⁵.
 8. The compound of claim 1 wherein R² is —NR^(a)S(O)₂R⁷.
 9. The compound of claim 1 wherein R² is —C(O)NR^(f)R⁸.
 10. The compound of claim 1 wherein m is 0 and n is
 1. 11. The compound of claim 1 wherein m is 1 and n is
 0. 12. A pharmaceutical composition comprising the compound of claim 1 and a pharmaceutically acceptable carrier.
 13. A pharmaceutical composition comprising the compound of claim 3 and a pharmaceutically acceptable carrier.
 14. A process for preparing a compound of formula (I),

or a pharmaceutically-acceptable salt or protected derivative thereof, wherein R¹, R², R⁹, R¹⁰, m, and n are defined as in claim 1, the process comprising: (a) reacting a compound of formula (II):

with (i) a compound of formula R^(3a)C(O)-L, wherein R^(3a) is R³ or a protected form of R³ and L is a leaving group or R^(3a)C(O)-L is a carboxylic acid or a carboxylate salt; (ii) a compound of formula R⁵—N═C═O; or (iii) a compound of formula R⁷S(O)₂-L′ where L′ is a leaving group; or (b) reacting a compound of formula (IId):

with a compound of formula HNR^(f)R⁸; and (c) optionally removing the protecting group or groups from R^(3a), to provide a compound of formula (I), or a pharmaceutically-acceptable salt or protected derivative thereof.
 15. A compound of formula (II):

wherein R¹, R⁹, R¹⁰, m and n are defined as in claim 1; or a salt thereof. 